F Hoffman‑La Roche & Co AG v Commissioner of Patents

RUTILE The mineral rutile, generally found in the form of large thick black or reddish brown crystals, is the most abundant of three naturally occurring forms of titanium dioxide (TiO2). Rutile is commercially significant for two reasons. First, it is the world's major source of titanium. Titanium's combination of high strength, low density and excellent resistance to corrosion makes it attractive for use in many of the parts in aircraft, spacecraft, missiles and ships. It is also used in prosthetic devices, because there is no reaction between titanium and fleshy tissues and bones, as a deoxidiser in steel, as an alloying addition in many steels and in aluminium to reduce grain size, in stainless steel to reduce carbon content, and in copper to reduce hardening. Second, titanium dioxide itself is widely used as a white pigment for exterior paints because of its chemical inertness, superior covering power, opacity to damaging ultraviolet light, and self‑cleaning ability. It is also used as a whitening or opacifying agent in other products ‑ paper, ceramics, rubber and leather, for example. Titanium dioxide is particularly used as an opacifying agent in porcelain enamels, giving a finishing coat of great brilliance, hardness and acid resistance. THE APPLICATION On 30 June 1994 the applicant ("WIM") applied for an injunction restraining the respondent ("RGC") from infringing Australian Petty Patent No 649,946, and for damages and other relief. In its statement of claim WIM alleged that it was registered under the Patents Act 1990 ("the Act") as the proprietor of the petty patent for an invention entitled "Production of Synthetic Rutile" which proceeded to grant and was published on 2 June 1994. In its particulars of infringement WIM specified, amongst other things, the manufacture or supply by RGC of synthetic rutile using a pilot project for the removal of impurities. The pilot project used the Synthetic Rutile Enhancement Process ("the SREP process"). The thermal reduction stage of the SREP process was conducted at Capel, Western Australia, and the kiln product was shipped to Narngula, Western Australia, for the subsequent aeration and acid leaching stages. By its defence and cross claim RGC contended that the petty patent was wholly invalid and sought an order that it be revoked. On 30 November 1994 WIM amended its application so as to rely on Australian Standard Patent No 639,089 as well as on the petty patent. In its amended statement of claim WIM alleged that it was registered as proprietor of the standard patent for an invention entitled "Production of Synthetic Rutile" which was published on 18 September 1991 and proceeded to grant on 11 May 1994. By its amended defence and cross claim RGC expanded its existing contentions to cover the standard patent. By notice of motion filed on 20 January 1997 WIM applied for orders that the standard patent be amended in accordance with the schedule to the notice. That is the application before me. Before setting out the amendments sought it is necessary to describe the standard patent specification as filed and as subsequently accepted, which is how it stands at present. SPECIFICATION AS FILED (a) General description of invention WIM filed its specification on 1 March 1991. The specification describes a process for producing synthetic rutile from a titaniferous ore. The aim of the invention is to upgrade the titanium content of the ore. The specification first describes the invention in a general way. The invention provides a process for the removal of all or part of any iron, magnesium, manganese and aluminium from the ore. Three basic steps are involved. The first is a reduction step. The iron content of the ore is partially converted to metal by gaseous or carbothermic reduction. In the second step the product of the first is subjected to an aqueous treatment, resulting either in the dissolution of the metallic iron content of the mineral or in the conversion of the metallic iron to a separable iron oxide product. In the third step the titaniferous product of the second step is subjected to a leaching treatment for at least partial removal of residual iron, magnesium, manganese and aluminium. The titaniferous product of leaching will thus have a particularly high titanium content, and may be used in place of natural rutile or other materials with a high titanium content. (b) Prior art The specification then deals with the prior art. Four techniques are described: (1) In the most commonly used technique the titaniferous mineral is reduced with coal or char in a rotary kiln at temperatures in excess of 1100oC. In this process the iron content of the mineral is substantially metallised. Sulphur is added to convert manganese impurities to sulphides. Following reduction the metallised product is cooled, separated from associated char, and subjected to aqueous aeration for removal of virtually all metallic iron as a separable fine iron oxide. The titaniferous product of separation is treated with 2‑5% aqueous sulphuric acid for dissolution of manganese and some residual iron. There is no substantial removal of magnesium or aluminium from the product at any stage, and iron removal is only effected in the aeration step. After calcination the synthetic rutile contains approximately 92% titanium dioxide and 1‑2% iron as oxide. The fact that this process does not remove the magnesium and aluminium in the titaniferous material is a drawback, because those impurities have deleterious effects in the production of white titanium dioxide pigment from synthetic rutile via the chloride process. This is the major use of synthetic rutile. (This technique is known as the "modified Becher process": Australian Patent 516,155 ‑ Hockin and Rolfe). (2) In another technique the ore (ilmenite) is thermally reduced to substantially complete reduction of its ferric oxide content, normally in a rotary kiln. The cooled reduced product is then leached under 35 psi pressure at 140‑150oC with excess 20% hydrochloric acid for removal of iron, magnesium, aluminium and manganese. The leach liquors are spray roasted for regeneration of hydrogen chloride, which is recirculated to the leaching step. (3) A third technique involves subjecting the ilmenite to grain refinement by thermal oxidation followed by thermal reduction in either a fluidised bed or rotary kiln. The cooled reduced product is then subjected to atmospheric leaching with excess 20% hydrochloric acid for removal of the deleterious impurities. Acid regeneration is also performed by spray roasting. (4) The final technique involves thermal reduction of ilmenite (without metallisation) with carbon in a rotary kiln, followed by cooling in a non oxidising atmosphere. The cooled reduced product is leached under 20‑30 psi gauge pressure at 130C with 10‑60% sulphuric acid in the presence of a seed material which assists hydrolysis of dissolved titanium, and consequently assists leaching of impurities. Hydrochloric acid can be used in this process instead of sulphuric acid. The major disadvantages of all processes using hydrochloric acid or sulphuric acid are then pointed out. In summary of the disadvantages of the prior art generally, it is said that existing processes will either not be effective in removing deleterious impurities, or will not be cost effective due to the need to regenerate large quantities of expensive reagents or to neutralise and dispose of large volumes of leachate liquors. It is the object of WIM's invention to overcome or at least alleviate some of these difficulties. (c) Consistory clause The steps involved in the invention are then set out: (i) reducing the titaniferous ore or concentrate under conditions which promote the formation of metallic iron, a major rutile phase and a minor impurity bearing phase; (ii) cooling the product of step (i) in an oxygen free environment; (iii) subjecting the cooled product of step (i) to a first stage leaching or aeration to convert metallised iron into a readily removable form; (iv) removing iron from the product of step (iii); (v) subjecting the product of step (iv) to a second stage leaching to convert other impurity elements to a removable form; and (vi) removing the other impurity elements from the product of step (v). (d) Body of specification The elements of the invention are then described in more detail. The iron present in the ore can be partially reduced to metallic iron by the use of coke, char or coal, gaseous fuels such as hydrogen, natural and petroleum gas, or liquid fuels. The temperature of reduction should be above 900oC in the case of solid carbonaceous reductants and above 600oC in the case of hydrogen bearing gaseous reductants. The preferred apparatus for reduction is a rotary kiln charged with a solid carbonaceous reductant such as coal, char or coke and operated with a maximum temperature in the range 950‑1050oC. Higher temperatures may be used, but should not exceed 1200oC because at that temperature large quantities of non rutile phases, particularly the anosovite/pseudobrookite like phase (M3O5), will be formed, and there will be a tendency for the mineral to sinter and accrete. Formation of M3O5 rather than metatitinate (M2O3) will result in the need to use more aggressive conditions in leaching. In general, degrees of metallisation in the range 50‑95%, depending on mineral composition, will be suitable. An appropriate degree of metallisation can be achieved by roasting the ore in the kiln for between 30 minutes and several hours at or above 900oC. After cooling and separation of carbonaceous material from minerals, metal may be removed by any suitable means. The preferred method is aqueous aeration, which converts the metal to iron oxides. After separation of the titaniferous product from the iron oxides, the product contains virtually all of its original magnesium, manganese and aluminium. It may also contain substantial quantities of residual iron oxides which have not been metallised or have adhered during an aeration process. Leaching with strong mineral acid, such as hydrochloric or sulphuric acid, is effective in removing these impurities. The preferred leaching is with excess 18‑20 wt% HCI. Greater than 80% removal of iron, magnesium and manganese, and partial removal of aluminium, may easily be achieved by this process. After separation of the leach liquor from the mineral, the mineral product is dried and calcined to remove moisture. The resulting synthetic rutile will contain more than 90% TiO2, depending on the level of impurities in the original titaniferous material and the presence of non titaniferous grains in the original mineral which are retained through the process. A number of optional additional steps can be incorporated in the process. Only one need be mentioned. In involves the mixing of additives, such as chlorides or oxides (eg MnO2), into the titaniferous material prior to reduction in order to redistribute the metallic iron produced via segregation reactions, thereby influencing metallic iron removal, or to encourage the formation of an acid leachable minor impurity bearing phase. Seven examples of laboratory and pilot scale tests illustrating the techniques disclosed are then given. It is not necessary to describe them. (e) The claims The claims with which the specification concludes are: 1. A Process for upgrading the titania content of a titaniferous ore or concentrate which process comprises the steps of:‑ (i) reducing the titaniferous ore or concentrate under conditions which promote the formation of metallic iron, a major rutile phase and a minor impurity bearing phase; (ii) cooling the product of step (i) in an oxygen free environment; (iii) subjecting the cooled product of step (i) to a first stage leaching or aeration to convert metallised iron into a readily removable form; (iv) removing leached or aerated iron from the product of step (iii); (v) subjecting the product of step (iv) to further leaching processes to convert other impurity elements to a readily removable form; and (vi) removing the other impurity elements from the product of step (v). 2. A process according to claim 1 wherein the minor impurity bearing phase is metatitanate (M2O3) or anosovite - pseudobrookite like phase (M3O5). 3. A process according to claim 1 or claim 2 wherein step (iii) comprises blowing air through an agitated aqueous suspension of the cooled product of step (i) in the presence of an agent that promotes the formation of oxides of iron. 4. A process according to claim 1 or claim 2 wherein step (iii) comprises leaching the cooled product of step (i) in a solution of a strong mineral acid. 5. A process according to any one of the preceding claims wherein step (v) comprises leaching the product of step (iv) in an agitated solution of a strong mineral acid. 6. A process according to claim 5 wherein the solution of strong mineral acid has an initial concentration in the range from 4 to 50 wt%. 7. A process according to claim 5 or claim 6 wherein the solution of strong mineral acid is maintained at a temperature in the range from 80 to 150oC. 8. A process according to claim 7 wherein the solution of strong mineral acid is refluxed. 9. A process according to any one of claims 4 to 8 wherein the strong mineral acid is hydrochloric acid or sulphuric acid. 10. A process according to any one of the preceding claims wherein step (i) comprises reducing the titaniferous ore or concentrate with a solid carbonaceous reductant at a temperature in the range from 900oC to 1200oC. 11. A process according to claim 10 wherein step (i) is performed at a temperature in the range from 900oC to 1050oC. 12. A process according to any one of claims 1 to 9 wherein step (i) comprises reducing the titaniferous ore or concentrate with a hydrogen bearing gaseous reductant at a temperature in the range from 600oC to 1200oC. 13. A process according to any one of the preceding claims wherein the process includes the preliminary step of oxidizing the titaniferous ore or concentrate at a temperature in excess of 700oC. 14. A process according to claim 1 wherein the minor impurity bearing phase is anosovite or pseudobrookite and step (v) comprises leaching the product of step (iv) in excess sulphuric acid whilst agitating the heated sulphuric acid for a period of from 15 minutes to 24 hours. 15. A process according to claim 14 wherein the acid has an initial concentration of up to 50 wt%. 16. A process according to claim 1 wherein the carbonaceous reductant is a sub‑bituminous or lignitic coal or char derived therefrom. SPECIFICATION AS ACCEPTED The specification was accepted by the Patents Office on 15 July 1993. The specification as filed was altered in a number of respects before acceptance. The specification as accepted is how it stands at present. The material differences between the two documents can be summarised as follows: (a) In the specification as accepted the first example of prior art is amplified by the statement that the addition of sulphur into the kiln has the negative environmental impact of producing sulphurous kiln exit gases. In the acid leach stage malodorous sulphide gases are commonly produced. The cost of countering these environmental impacts is considerable, and has been influential in preventing the use of sulphur in at least one synthetic rutile installation. (b) A further example of prior art is given in the specification as accepted. In this process ilmenite is first metallised by fluidised bed reduction with hydrogen or carbon monoxide, followed by aqueous aeration for metallic iron removal as separable iron oxides. The titaniferous product of aeration is then optionally acid leached for upgrading from 85‑89% to about 96% TiO2, with removal of residual impurities. The weaknesses of this process are that the use of gaseous reductants is associated with poor single pass reductant utilisation, fluidised beds are limited in maximum temperature when applied to ilmenite metallisation by gaseous reductants since bed sintering occurs at temperatures over 800‑900oC, and metallisation rates at lower temperatures at which effective fluidisation is achieved are low. Consequently, either highly inefficient use of reductant at low intensities is involved, or high pressure processing with reductant recycle is required. (This technique is known as "the Auger process"). (c) After the examples of prior art, and before the summary of the shortcomings of the existing processes, the specification as accepted contains additional material which can be summarized as follows. The prior art is silent on the possibility of metallisation of magnesium and manganese rich ilmenites using solid carbonaceous reductant at temperatures above 900oC followed by aeration for metal removal and acid leaching for removal of magnesium and other residual impurities. At temperatures above about 900oC carbothermic metallisation of ilmenite becomes achievable under practical conditions. However, as presently disclosed, under many conditions a residual impurity bearing titanium phase which cannot easily be leached of all impurities is formed. In particular, the formation of this phase is enhanced by the presence of magnesium in the original ilmenite. There has been no prior disclosure of the required thermal processing or leach conditions which encourage particular impurity bearing phases to form and then be effectively leached. The lower temperature fluidised bed metallisation work has allowed successful leaching of impurities due to a structure present in the residual impurity bearing phase which has not previously been reported as exclusively available under product metallisation conditions at higher temperature. (d) The cost penalties listed in the summary of deficiencies of the existing processes is expanded by reference to the need to operate largely impractical and economically unattractive thermal processing schemes. (e) The consistory clause is amended in one important respect. In step (i) the expression "a separate minor impurity bearing phase" is replaced by "a separate minor impurity bearing titaniferous phase". Changes of a cosmetic nature are made to other steps. (f) The description of step (i) in the body of the specification as accepted no longer refers to gaseous or liquid fuel reductants. (g) The claims defining the invention are reduced by the omission of the former claim 13. The steps of claim 1 have been recast and are: (i) reducing the titaniferous ore or concentrate using a solid carbonaceous reductant under temperature conditions which promote the formation of metallic iron, a major rutile phase and a separate minor impurity bearing titaniferous phase to produce a reduced product; (ii) cooling the reduced product of step (i) in an oxygen free environment to produce a cooled reduced product; (iii) subjecting the cooled reduced product of step (i) to a first stage leaching or aeration to convert metallised iron into a readily removable form to produce a leached or aerated product; (iv) removing iron from the leached or aerated product of step (iii) to produce an intermediate product; (v) subjecting the intermediate product of step (iv) to further leaching processes to form a residue and convert other impurity elements to a readily removable form; and (vi) removing the other impurity elements from the residue of step (v) to produce a synthetic rutile. The principal change is in step (i). The expression "a minor impurity bearing phase" is replaced by "a separate minor impurity bearing titaniferous phase", and "conditions which promote" has been changed to "temperature conditions which promote". The changes to other steps are of a cosmetic nature. Some of the later claims have been amended to reflect those cosmetic changes. Step 12 has been altered by the deletion of the words "at a temperature in the range from 600oC to 1200oC". AMENDMENTS SOUGHT The amendments sought relate to the consistory clause and the claims defining the invention. The amendments to the former reflect certain of the amendments to the latter, and it is not necessary to note them separately. The changes to claims 1 and 2 can be seen from the following marked up claims in which the passages in square brackets are to be deleted and the underlined passages are to be added: 1. A process for upgrading the titania content of a titaniferous ore or concentrate which process comprises the steps of:‑ (i) reducing the titaniferous ore or concentrate using a solid carbonaceous reductant at a temperature of at least 900oC to form [under temperature conditions which promote the formation of] metallic iron, a major rutile phase and a separate minor impurity bearing titaniferous phase containing impurities that are in the titaniferous ore or concentrate to produce a reduced product; (ii) cooling the reduced product of step (i) in an oxygen free environment to produce a cooled reduced product; (iii) subjecting the cooled reduced product of step (ii) [(i)] to a first stage leaching or aeration to convert metallised iron into a readily removable form to produce a leached or aerated product; (iv) removing the readily removable form of the iron from the leached or aerated product of step (iii) to produce an intermediate product; (v) subjecting the intermediate product of step (iv) to [further] leaching [processes] with a solution of a strong acid to form a residue and convert other impurity elements to a readily removable form, said other impurity elements being impurities in the separate minor impurity bearing titaniferous phase in the reduced product of step (i); and (vi) removing the readily removable form of the other impurity elements from the residue of step (v) to produce a synthetic rutile. 2. A process according to claim 1 wherein the separate minor impurity bearing titaniferous phase in the reduced product of step (i) is a metatitanate (M2O3) phase [or a anosovite/pseudobrookite like phase (M3O5)]. Claims 3 to 8, which are to be added, are as follows: 3. A process according to claim 1 wherein the separate minor impurity bearing titaniferous phase in the reduced product of step (i) is an anosovite/pseudobrookite phase (M3O5). 4. A process according to any one of the preceding claims further comprising mixing an additive into the titaniferous ore or concentrate to encourage the formation of the separate minor impurity bearing titaniferous phase in the reduced product of step (i). 5. A process according to claim 4 wherein the additive is an oxide or oxides. 6. A process according to any one of the preceding claims comprising reducing the titaniferous ore or concentrate in step (i) under conditions which minimise the amount of an anosovite/pseudobrookite (M3O5) phase relative to an alternative separate minor impurity bearing titaniferous phase in the reduced product of step (i). 7. A process according to any one of the preceding claims wherein the degree of conversion of iron in the titaniferous ore or concentrate to metallic iron in reduction step (i) is at least 50%. 8. A process according to claim 7 wherein the degree of conversion of iron in the titaniferous ore or concentrate to metallic iron in reduction step (i) is in the range of 50‑95%. Claim 10, which is to be renumbered 9, is to be amended as follows: 9. A process according to any one of the preceding claims wherein the reduction temperature of step (i) is less than [step (i) comprises reducing the titaniferous ore or concentrate with a solid carbonaceous reductant at a temperature in the range from 900oC to] 1200oC. The new claim 10 will read: 10. A process according to any one of the preceding claims wherein step (i) is carried out in a rotary kiln operated at a maximum temperature greater than 950oC. Claim 11 is to be amended as follows: 11. A process according to any one of the preceding claims [claim 10] wherein step (i) is carried out in a rotary kiln operated at a maximum temperature less than [performed at a temperature in the range from 900oC to] 1050oC. Claims 12 to 14 are to be deleted. Claims 12 to 24, which are to be added, are as follows: 12. A process according to any one of the preceding claims wherein step (i) is carried out in a rotary kiln operated at a maximum temperature in the range of 950‑1050oC. 13. A process according to any one of the preceding claims wherein the impurities that are in the titaniferous ore or concentrate comprise any one or more of manganese, magnesium, and aluminium. 14. A process according to claim 13 wherein step (v) converts at least part of the manganese that is in the titaniferous ore or concentrate to the readily removable form. 15. A process according to claim 13 or claim 14 wherein step (v) converts at least part of the magnesium that is in the titaniferous ore or concentrate to the readily removable form. 16. A process according to any one of claims 13 to 15 wherein step (v) converts at least part of the aluminium that is in the titaniferous ore or concentrate to the readily removable form. 17. A process according to any one of the preceding claims wherein step (v) converts at least part of the iron that is not removed in step (iv) to a readily removable form. 18. A process according to claim 13 wherein step (i) concentrates manganese in the titaniferous ore or concentrate into the separate minor impurity bearing titaniferous phase in the reduced product of step (i). 19. A process according to claim 18 wherein step (v) converts a substantial part of the manganese in the separate minor impurity bearing titaniferous phase in the reduced product of step (i) to the readily removable form. 20. A process according to claim 19 wherein step (v) converts at least 80% of the manganese in the separate minor impurity bearing titaniferous phase in the reduced product of step (i) to the readily removable form. 21. A process according to any one of claims 13 and 18 to 20 wherein step (i) concentrates magnesium in the titaniferous ore or concentrate into the separate minor impurity bearing titaniferous phase in the reduced product of step (i). 22. A process according to claim 21 wherein step (v) converts a substantial part of the magnesium in the separate minor impurity bearing titaniferous phase in the reduced product of step (i) to the readily removable form. 23. A process according to claim 22 wherein step (v) converts at least 80% of the magnesium in the separate minor impurity bearing titaniferous phase in the reduced product of step (i) to the readily removable form. 24. A process according to any one of claims 13 and 18 to 23 wherein step (v) converts at least a part of the aluminium in the separate minor impurity bearing titaniferous phase in the reduced product of step (i) to the readily removable form. Claims 3 to 5, which are to be renumbered 25 to 27, are to be amended as follows: 25. A process according to any one of the preceding claims [claim 1 or claim 2] wherein step (iii) comprises blowing air through an agitated aqueous suspension of the cooled reduced product of step [(i)] (ii) in the presence of an agent that promotes the formation of oxides of iron. 26. A process according to any one of the preceding claims [claim 1 or claim 2] wherein step (iii) comprises acid leaching the cooled reduced product of step (ii) [(i) in a solution of a strong mineral acid]. 27. A process according to any one of the preceding claims wherein the strong acid in [step (v) comprises leaching the intermediate product of] step (v) is [in] an agitated solution of a strong mineral acid. A new claim 28 is to be added: 28. A process according to claim 27 wherein the solution of the strong mineral acid has a concentration in the range of 4‑20wt%. Claims 6 to 9 and 15, which are to be renumbered 29 to 33, are to be amended as follows: 29. A process according to claim 27 [5] wherein the solution of the strong mineral acid has a [an initial] concentration in the range of 4‑50 [4 to 50] wt%. 30. A process according to any one of claims 27 to 29 [claim 5 or claim 6] wherein the solution of the strong mineral acid is maintained at a temperature in the range from 80 to 150oC. 31. A process according to claim 30 [7] wherein the solution of the strong mineral acid is refluxed. 32. A process according to any one of claims 27 to 31 [4 to 8] wherein the strong mineral acid is hydrochloric [acid] or sulphuric acid. 33. A process according to any one of the preceding claims [claim 1] wherein the solid carbonaceous reductant is sub‑bituminous or lignitic coal or char derived therefrom. AMENDMENT PROVISIONS Section 105(1) of the Act empowers the Court to direct the amendment of a patent, the patent request or the complete specification in the manner specified in its order. As a result of sub-s(4) an amendment is not to be directed which is not allowable under s102. That section is in part as follows: (1) An amendment of a complete specification is not allowable if, as a result of the amendment, the specification would claim matter not in substance disclosed in the specification as filed. (2) An amendment of a complete specification is not allowable after the specification has been accepted if, as a result of the amendment: (a) a claim of the specification would not in substance fall within the scope of the claims of the specification before amendment; or (b) the specification would not comply with subsection 40(2) or (3). (3) This section does not apply to an amendment for the purpose of correcting a clerical error or an obvious mistake made in, or in relation to, a complete specification. Section 40(2) requires that a complete specification describe the invention fully, including the best method known to the applicant of performing the invention, and end with a claim or claims defining the invention. Sub-section (3) requires the claim or claims to be clear and succinct and fairly based on the matter described in the specification. OBJECTIONS TO AMENDMENT RGC has objected to the amendment on two grounds. The first is that the amendment is not allowable under s102 for the following reasons: as a result of the amendment the specification would claim matter not in substance disclosed in the specification as filed; as a result of the amendment certain of the claims would not in substance fall within the scope of the claims of the specification before amendment; as a result of the amendment the specification would not comply with s40(2) or (3) because the specification would not describe the invention fully, it would not describe the best method known to the applicant of performing the invention, each of the claims would not define the invention and would not be clear and succinct, and each of the claims would not be fairly based on the matter described in the specification. The second ground is that the amendment should be refused in the exercise of the Court's discretion. CONSTRUCTION OF s 102 Section 18(8) of the Patents, Designs, and Trade Marks Act 1883 (UK) provided that no amendment shall be allowed that would make the specification, as amended, claim an invention substantially larger than or substantially different from the invention claimed by the specification as it stood before the amendment. Section 78 of the Patents Act 1903 (Cth) was in the same form. Section 31(1) of the Patents Act 1949 (UK) provided: After the acceptance of a complete specification, no amendment thereof shall be effected except by way of disclaimer, correction or explanation, and no amendment thereof shall be allowed, except for the purpose of correcting an obvious mistake, the effect of which would be that the specification as amended would claim or describe matter not in substance disclosed in the specification before the amendment, or that any claim of the specification as amended would not fall wholly within the scope of a claim of the specification before the amendment. The phrase in s31(1) ‑ "matter not in substance disclosed in the specification before the amendment" ‑ is essentially the same as that in s 102(1) of the Act ‑ "matter not in substance disclosed in the specification as filed". In Ethyl Corporation's Patent [1972] RPC 169, a case which turned on the words "matter not in substance disclosed in the specification before the amendment" in s 31(1), Salmon LJ said at 193‑194: From 1883 until after the end of the last war, the courts tended to regard patent monopolies with some disfavour as being generally contrary to the public interest. Since, at any rate, 1949, the climate of opinion has changed. It is now generally recognised that it is in the public interest to encourage inventive genius. Accordingly the modern tendency of the courts has been to regard patent claims with considerably more favour than formerly. Section 31(1) of the Patents Act, 1949 was, in my view, intended to liberalise the law as laid down in section 18(8) of the Patents, Designs, and Trade Marks Act, 1883 .... Cross LJ said at 192 that s 31(1) should be construed in "a broad common sense way". Lord Denning MR, who agreed with the other judgments, said at 195: I do not think it is of much use going back to the old cases before 1883: nor to those before 1949. Section 31(1) should be given a liberal interpretation so as to permit any fair amendment which has already been in substance disclosed. [Counsel opposing the amendment] ... relied upon the provisions of sections 4(4) and 32(1)(i) of the Act, which required that any claim must be "fairly based" on the matter disclosed in the specification. He said that this claim was not so "fairly based". It is true that this requirement of "fairly based" is virtually the same as the requirement that the amendment must be "in substance disclosed". But the answer is the same. It was fairly based as well as being in substance disclosed. Save that it dealt with amendments to petty patent specifications as well as complete specifications, s 78 of the 1952 Act was in substantially the same form as s 102 of the Act. While s 78 was not in all respects the same as s 31(1) of the 1949 Act, it was clearly modelled on it. And s 78 of the 1903 Act was in the same terms as s 18(8) of the 1883 Act. In my view s 78 of the 1952 Act was intended to liberalise the law as laid down in s 78 of the 1903 Act. Accordingly s 102 should be given a liberal interpretation. As Lord Denning said in the Ethyl case, the "in substance disclosed" limb of s 31(1) is virtually the same as the "fairly based" requirement in ss 4(4) and 32(1)(i) of the 1949 Act. Cf ss 40(3) and 138(3)(f) of the Act. Counsel on both sides referred to, and with different degrees of emphasis relied on, the fair basis cases. In F Hoffman‑La Roche & Co AG v Commissioner of Patents (1971) 123 CLR 529, a case concerning one of the "fairly based" provisions of the 1952 Act, Gibbs J said: The question whether a claim in a complete specification is fairly based on matter disclosed in the provisional specification was considered by the Patents Appeal Tribunal, constituted by Lloyd‑Jacob J, in Re Mond Nickel Company Ltd's Application [1956] RPC 189 at 194 and Imperial Chemical Industries Ltd's Application [1960] RPC 223 at 228. ... Lloyd‑Jacob J did not attempt to define all that is meant by the phrase "fairly based" but he gave a guide to the approach that should be made in deciding a question of this kind. In his opinion it is necessary to investigate three questions ...: (1) Is the alleged invention as claimed broadly (ie in a general sense) described in the basic application? (2) Is there anything in the basic application which is inconsistent with the alleged invention as claimed? (3) Does the claim include as a characteristic of the invention a feature as to which the basic application is wholly silent? Gibbs J went on to say that these questions are intended to assist the court in applying the test laid down by the legislation itself, and are not a substitute for that test. His Honour then referred to the observations of Fullagar J in Société des Usines Chimiques Rhône‑Poulenc v Commissioner of Patents (1958) 100 CLR 5 at 11, that s 45(5) of the 1952 Act ("a claim fairly based on matter disclosed in the ... specification lodged under the repealed Acts") was not limited to cases where the subject matter of the later application has been made the subject of a specific claim in the earlier application, and that there must be "a real and reasonably clear disclosure". Another question of construction is whether the power to amend extends to converting an optional feature of an invention into an essential feature. RGC claims that it does not, because the optional feature is not part of the invention. One of the issues considered in AMP Incorporated v Hellerman Ltd [1962] RPC 55 was whether a feature clearly disclosed in the specification as an optional part of the device claimed could be incorporated into a claim by way of amendment under s 31(1) of the 1949 Act. It was held by Lord MacDermott, Lord Radcliffe and Lord Denning that it could, provided that its inclusion operated "by way of disclaimer". Viscount Simonds, with whom Lord Devlin agreed, dissented in the result, but did not mention the optional/essential issue. Lord Denning said at 70: If you read carefully through the complete specification as filed without any amendment, you will see that the pawl and ratchet device ... is one of the essential features of the invention ... You will also see from the specification that a "stop" is disclosed as an optional feature, though not as an essential feature. ... Now the point in the case is this: The patentees wish to amend their specification so as to elevate the "stop" into an essential feature. Instead of being merely optional, they wish to make it one of the essential features of the invention .... Now this amendment cannot be effected unless it is permitted by s 31(1) ...: and for this purpose (1) it must be "by way of disclaimer" and (2) the matter contained in it must already be "in substance disclosed in the specification before the amendment". His Lordship dealt first with the "disclaimer" limb, and concluded that by making the "stop" an essential part of the invention the patentee had reduced the ambit of the monopoly, and thus the amendment was a disclaimer. He then turned to the "disclosure" limb, and said at 71‑72: Even though there is a "disclaimer", however, the amendments cannot be allowed under s 31(1) if "the specification, as amended, would claim or describe matter not in substance disclosed in the specification before the amendment". There is no difficulty on this point. The "stop" was clearly disclosed in the original specification. It is true that it may not have been a "distinctive" part of the tool, nor was it put forward as an "inventive step" in itself. But that does not matter under the 1949 Act. Sufficient if it was in substance disclosed in the original specification: and that it clearly was. It seems to me that where the Court of Appeal fell into error was because they approached this case much as the courts approached such cases under the previous Act. They looked to the original specification so as to see what were the "inventive steps" claimed by it. They found that the emphasis was all on the pawl and ratchet device to prevent "under crimping", and not on the stop to prevent "over‑crimping". They thought, therefore, that the patentee, so far from disclaiming anything by the amendment, was seeking to alter the emphasis of the specification, so as to add prevention of over‑crimping to prevention of under‑crimping. In short, the patentee was not disclaiming any "inventive step", but claiming a fresh one. If that were so, it would under the old law have been a good objection to an amendment, because the patentee would be claiming an invention "substantially different" from the invention claimed by the specification. ... Parliament has altered the old law. It is no longer necessary to inquire into the niceties of inventive steps. It is only necessary to see whether the matter was in substance disclosed in the original specification, and that it clearly was. I would agree that if the amendment had introduced an entirely new integer, that is to say, a feature that had not been disclosed in the specification previously, then it could not have been allowed. But here there is no new integer. The "stop" was clearly disclosed in the original specification. All that is done is to make it an essential feature, whereas it was previously optional. And this, in my opinion, is permissible under the 1949 Act. Lord MacDermott's speech was to the same effect. See at 68‑69. Lord Radcliffe agreed with the speeches of Lord MacDermott and Lord Denning. COMPARISON CONTEMPLATED BY s 102(1) In a case such as the present where the specification as it stands differs from the specification as filed, the comparison contemplated by s 102(1) is not, in my view, directly between the specification as filed and the specification as sought to be amended. A two stage process is involved. The first stage involves a comparison between the specification as it stands and how it would stand after amendment. Once the matter resulting from the amendment has been identified, that matter is compared with the specification as filed in order to determine whether the specification as amended would claim matter not in substance disclosed in the specification as filed. MATTERS NOT IN SUBSTANCE DISCLOSED In RGC's Statement of Grounds and Particulars of Objection ("the Objections") it was asserted that there were twenty six respects in which, as a result of the amendments, the specification would claim matter not in substance disclosed in the specification as filed. However only seven "non‑disclosures" were relied on in RGC's Outline of Argument, and not all of them were pursued in oral argument. (a) "at a temperature of at least 900oC to form" Step (i) of claim 1 as it stands refers to the use of a solid carbonaceous reductant "under temperature conditions which promote the formation of" metallic iron. The quoted words are to be replaced by "at a temperature of at least 900oC to form". Thus the effect of the amendment is to set a lower limit to the temperature to be employed. Instead of the temperature being one which promotes a particular result, the lower limit of the temperature is specified. Is the claim to a temperature of at least 900oC in the reduction process in step (i) in substance disclosed in the specification as filed? In the body of the specification, immediately after the consistory clause, when describing step (i), it is said that the "temperature of reduction should be above 900 oC in the case of solid carbonaceous reductants". Then it is said that the preferred apparatus in which the reduction is carried out is a rotary kiln charged with sold carbonaceous reductant operated "with a maximum temperature in the range 950‑1050oC". A little further on it is said that a suitable degree of metallisation can be achieved "at or above 900 oC for carbothermic reduction in a rotary kiln". The examples show temperatures of 950oC, 1000oC, 950 + 50oC, above 900oC and 900oC. In my view the claim that the temperature be at least 900oC is in substance disclosed in the specification as filed. While the question whether or not a feature sought to be added is in substance disclosed turns on the facts of the particular case, the present case is not unlike Ethyl. In the claim sought to be amended there, a compound was merely required to be present in the combination. By the amendment the patentee sought to limit the presence of the compound to between 20 and 80% of another constituent. In the unamended specification the range as such was not specified, but examples were given having percentages falling within the range. The Court of Appeal held that the unamended specification fairly disclosed the whole range and that it was therefore permissible to disclaim down to the limited range. Lord Denning said at 194‑195: The amendment is clearly by way of disclaimer, because it limits the wide claim in the original claim 14 (which gives an unlimited range) to a particular claim in the new claim 14 (which limits it to the numerical range from 20 to 80). The amendment is "in substance disclosed in the specification before the amendment" because the original specification contains examples of compositions within the new range of 20 to 80. It is I think unnecessary for the original specification to use words or figures describing the limits of the range (eg words saying that a useful application is in the range from 20 to 80). It is sufficient if the original specification discloses instances of application within that range. [Counsel opposing the amendments] sought to use an analogy. He said that it is not sufficient for the original specification to set out marker posts: but that it must also draw a line round the boundary fence. I do not agree. The range is sufficiently disclosed by the marker posts. It is not necessary to draw a line round them. The amendment at present under consideration more clearly does not offend s 102(1) than the amendment in the Ethyl case did not offend s 31(1). There it was necessary to resort to the examples in order to find instances of compositions within the new range. Here it is not necessary to resort to the examples (though they do fill that role), because the body of the specification shows that the optimum temperature is above 900oC. The same conclusion is reached if one approaches the matter by way of the guidelines in Mond Nickel. As to the first, the new matter (the lower limit of 900oC for a solid carbonaceous reductant) is broadly or in a general sense described in the specification as filed. As to the second guideline, there is nothing in the specification as filed which is inconsistent with the lower limit of 900oC for a solid carbonaceous reductant. As to the third, the 900oC lower limit for the roasting stage with a solid carbonaceous reductant is not a feature as to which the specification as filed is wholly silent. On the contrary, that feature is set out at least twice. And applying the observation of Fullagar J in Rhône‑Poulenc, the specification as filed does make a real and reasonably clear disclosure of the fact that the preferred lower limit to the temperature of the roasting stage is 900oC. For the foregoing reasons, I reject RGC's contention that the insertion of the lower limit of 900 oC would result in the specification claiming matter not in substance disclosed in the specification as filed. (b) "separate minor impurity bearing titaniferous phase" This amendment in effect defines the "other impurity elements" in step (v) of claim 1 ‑ "said other impurity elements being impurities in the separate minor impurity bearing titaniferous phase in the reduced product of step (i)". RGC points out that the specification as filed contains no limitation to the effect that the minor impurity bearing phase be titaniferous. This is true, but it does not follow that s 102(1) is offended. As I have said, the direct comparison between the specification as filed and as notionally amended is not the exercise contemplated by the sub‑section in its application to a case such as the present. What must be dermined is whether as a result of the amendment the specification would claim matter not in substance disclosed in the specification as filed. So one first ascertains the change the amendment effects to the specification as it stands immediately before the amendment. Having done that, one asks whether the effect of the change is that the specification claims matter not in substance disclosed in the specification as filed. Step (i) as it stands reduces the titaniferous ore so as to form metallic iron, a major rutile phase and a separate minor impurity bearing titaniferous phase. Steps (ii), (iii) and (iv) are concerned with the removal of metallised iron. What is left is a major rutile phase and a separate minor impurity bearing titaniferous phase. Plainly the "other impurity elements" to which step (v) refers are the impurities in that phase, namely magnesium, manganese, aluminium and any residual iron oxides which had not been metallised or which had adhered during an aeration step. What the amendment does is to spell that out. Thus, while the claims in the specification as filed make no mention of a minor impurity bearing titaniferous phase, that is of no moment because the disparity between the specification as filed and the notionally amended specification does not result from the amendment. As a matter of construction the introduced words are implicit in step (v) as it presently stands. Accordingly I reject the contention that the insertion of a definition of impurity elements would mean that the specification would claim matter not in substance disclosed in the specification as filed. (c) claim 4 ‑ additive There is no substance in the contention that proposed claim 4 would offend s 102(1). One of the optional steps described on page 9 of the specification as filed is the mixing of an additive, such as a chloride or an oxide, into the titaniferous material prior to reduction to encourage the formation of an acid leachable "minor impurity bearing phase". It is true that the word "titaniferous" does not appear in the description of the phase. But that difference between the proposed claim and the specification as filed does not result from the amendment, because as a matter of construction of the specification as it stands, the phrase in the additive option ‑ "minor impurity bearing phase" ‑ means the minor impurity bearing titaniferous phase. Step (i) in the consistory clause speaks of reducing the titaniferous ore under temperature conditions which promote the formation of, inter alia, a separate minor impurity bearing titaniferous phase. The description of step (i) in the body of the specification discloses that the various impurities are predominantly concentrated into a small amount of a separate titaniferous phase. Step (i) of claim 1 repeats the phrase in the consistory clause ‑ "separate minor impurity bearing titaniferous phase". Any additive is to be mixed into the titaniferous mineral prior to reduction. It follows that the reference in the additive clause to a "minor impurity bearing phase" must be to a minor impurity bearing titaniferous phase, because that is the result, elsewhere described in the document, of the reduction process. As the AMP case shows, it is no objection under s 102(1) that an amendment converts an optional feature of an invention into an essential one, so long as the optional feature is in substance disclosed by the specification. Thus RGC's claim that there is no disclosure of the additive fails. (d) claims 2 and 3 Claim 2 originally claimed a process according to claim 1 wherein the minor impurity bearing phase is a metatitanate (M2O3) or anosovite ‑ pseudobrookite like phase (M3O5). The amendment splits the claim into two ‑ one dealing with M2O3 and the other with M3O5. RGC contends that this amendment infringes s 102(1) for want of any disclosure in the examples or otherwise in either specification of the minor impurity phase being M2O3 to the exclusion of M3O5 or vice versa. Claim 2 as filed permits an alternative wherein the minor impurity bearing phase is M2O3 or M3O5. In the body of the specification (page 6) it is said that the minor impurity bearing phase may have either the anosovite/pseudobrookite M3O5 structure or an ilmenite‑like M2O3 structure. Splitting up the alternatives in claim 2 so that one is in proposed claim 2 and the other in proposed claim 3 does not result in the amended specification claiming matter not in substance disclosed in the specification as filed. (e) claim 6 RGC's complaint here is that the proposed claim speaks of "conditions" which minimise the amount of the M3O5 phase whereas the specification as filed mentions only one condition, namely temperature of less than 1200oC. The specification describes the preferred method as reduction in a rotary kiln charged with solid carbonaceous reductant and operated at a temperature below 1200oC. Those elements of the method are aptly described as "conditions" which minimise the M3O5 phase. There is no reason to restrict the minimisation factor to temperature alone. RGC's attack on claim 6 is at odds with the liberal construction that is to be given to s 102(1). (f) claims 7 and 8 These respectively claim a process wherein the degree of conversion of iron in the ore to metallic iron is at least 50% (claim 7) or in the range 50 ‑ 95% (claim 8). Although in the Objections the claims are attacked under s 102(1), no argument was addressed on the matter. Cf the attack on the claims under s 102(2) in pars 19 and 20 of RGC's Preliminary Outline of Argument and par 24(c) of its Outline of Submissions, which was abandoned. In any event, an attack based on s 102(1) would fail. On page 6 of the specification as filed it is said that, in general, degrees of metallisation in the range 50 ‑ 95%, depending on mineral composition, will be suitable. The proposed claims thus claim matter disclosed in the specification. (g) claims 13 to 24 These proposed claims deal with the individual impurities in the separate minor impurity bearing titaniferous phase in the reduced product of step (i). The impurities are manganese, magnesium, aluminium and iron that is not removed in step (iv). Thus claims 14 to 17 relate to the conversion of at least part of each impurity to a readily removable form. Claim 18 deals with the concentration of manganese in the ore into the separate minor impurity bearing titaniferous phase in the reduced product of step (i). Claims 19 and 20 deal with the conversion of a substantial part (claim 19) or at least 80% (claim 20) of the manganese in the impurity bearing phase to a readily removable form. Claim 21 is the magnesium counterpart of claim 18 (manganese). Claims 22 and 23 are the magnesium counterparts of claims 20 and 21 (manganese). Claim 24 deals with the conversion of at least part of the aluminium in the impurity bearing phase to a readily removable form. All these matters are in substance disclosed by the specification as filed. The general description of the invention on page 1 describes it as a process for the removal of iron, magnesium, manganese and aluminium from titanium bearing mineral ores. On page 2 general step (iii) is said to result in at least partial removal of residual iron, magnesium, manganese and aluminium. On page 8 it is said that leaching with strong acid is effective in removing the magnesium, manganese, aluminium and residual iron oxides, and it is claimed that greater than 80% removal of iron, magnesium and manganese, and partial removal of aluminium, may be achieved in this way. Some of the examples show the percentages of the impurities removed. Thus in batch 2 in Example 5 the removal rate is iron (96.5%), manganese (88.9%), magnesium (80.9%) and aluminium (18.0%). In my view these proposed claims do not claim matter not in substance disclosed in the specification as filed. SECTION 102(2)(a) Two complaints are made under this head, though they were not pleaded. The first is that as a result of adding the words "at a temperature of at least 900oC" in step (i) of claim 1, that claim would not in substance fall within the scope of the claims before amendment. The second is that as a result of replacing the words in step (v) ‑ "subjecting the intermediate product of step (iv) to further leaching processes to form a residue and convert other impurity elements to a readily removable form" ‑ with "subjecting the intermediate product of step (iv) to leaching with a solution of strong acid to form a residue and convert other impurity elements to a readily removable form", the claim would not so fall. Section 102(2)(a) is concerned with the scope of the claims. It disallows amendments the effect of which is that something which before amendment would not be an infringement would be an infringement after amendment. If an amended claim would fall within the scope of the claim before amendment, s 102(2)(a) will not be offended. Thus narrowing of an existing claim will not be obnoxious to s 102(2)(a). That is what the temperature amendment to step (i) does. Instead of the quite general "under temperature conditions which promote the formation of", the claim is narrowed to "a temperature of at least 900oC". As I understand the argument, it is that there is a difference between a temperature which promotes the formation of metallic iron, a major rutile phase and a separate minor impurity bearing titaniferous phase, and a temperature which causes metallic iron and those phases to form. Mr Catterns was unable to explain the difference, and I do not think there is a difference. If metallic iron and the two phases are in fact formed by the temperature applied, that temperature must be such as to promote their formation. Contrary to RGC's submission, the amendment does not make it easier to infringe the patent. The amendment to step (v) narrows the claim. Instead of "further leaching processes", there is but one leaching process claimed ‑ leaching with a solution of strong acid. Mr Catterns argued, however, that it would be easier to infringe the patent in its amended form than in its unamended form. In order to establish infringement of the patent as it stands, the patentee would have to establish that the intermediate product had been subjected to more than one leaching process, whereas after amendment he would only have to show subjection to one leaching process. A reading of the specification as a whole dispels any suggestion that more than one leaching process is involved in step (v). In dealing with step (v) the preamble speaks of "a second stage leaching step" and "a leaching treatment". In the body of the specification dealing with step (v) reference is made to "leaching with strong mineral acid", to what might advantageously be done "prior to leaching", to the fact that "leaching with excess 18‑20 wt% HCI has been found to be particularly advantageous", that "acid leaching may be conducted in any suitable batch or continuous leach vehicle, that "the leach step" can be operated without the need for pressure vessels, that leaching time may be from 15 minutes to 24 hours, and that "the described process" is effective to achieve greater than 80% removal of impurities. It is clear from these references that but one leach step or leaching treatment is involved in stage (v). All relevant examples involve only one leach at step (v). Example 1 involves 24 hours of leaching, Example 2 involves 31 hours of leaching, and Example 3 "four hours of the final leach". Example 4 deals only with the thermal reduction step. Example 5 involves leaching for up to 24 hours. Example 6 speaks of the "final leach". Accepted principles of construction permit resort to the body of the specification in order to understand the claims. Thus in Electric & Musical Industries v Lessen ("EMI") (1938) 56 RPC 23 at 41 Lord Russell of Killowen said: The prima facie meaning of words used in a claim may not be their true meaning when read in the light of [a dictionary found elsewhere in the specification or of technical knowledge possessed by persons skilled in the art]; and in those circumstances a claim, when so construed, may have a meaning different from that which it would have borne had no such assisting light been available. That is construing a document in accordance with the recognised canons of construction. In Rosedale Associated Manufacturers Ltd v Carlton Tyre Saving Co Ltd [1960] RPC 59 at 69 Lord Evershed MR said: It is no doubt true ... that you must construe the claims according to their terms upon ordinary principles, and that it is not legitimate to confine the scope of the claims by reference to some limitation which may be found in the body of the specification but is not expressly or by proper inference reproduced in the claims themselves. On the other hand, it is clearly no less legitimate and appropriate in approaching the construction of the claims to read the specification as a whole. Thereby the necessary background is obtained and in some cases the meaning of the words used in the claims may be affected or defined by what is said in the body of the specification. In Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183 at 242‑243 Lord Diplock, with whom the other members of the House of Lords agreed, said: A patent specification should be given a purposive construction rather than a purely literal one derived from applying to it the kind of meticulous verbal analysis in which lawyers are too often tempted by their training to indulge. The question in each case is: whether persons with practical knowledge and experience of the kind of work in which invention was intended to be used, would understand that strict compliance with a particular descriptive word or phrase appearing in a claim was intended by the patentee to be an essential requirement of the invention so that any variant would fall outside the monopoly claimed, even though it could have no material effect upon the way the invention worked. Six of the ten rules of construction that Sheppard J in his valuable judgment in Decor Corporation Pty Ltd v Dart Industries Inc (1988) 13 IPR 385 at 400 distilled from the authorities are relevant here. They are: (1) The claims define the invention which is the subject of the patent. These must be construed according to their terms upon ordinary principles. Any purely verbal or grammatical question that can be answered according to ordinary rules for construction of written documents is to be resolved accordingly. (2) It is not legitimate to confine the scope of the claims by reference to limitations which may be found in the body of the specification but are not expressly or by proper inference reproduced in the claims themselves .... (3) Nevertheless, in approaching the task of construction, one must read the specification as a whole. (4) In some cases the meaning of the words used in the claims may be qualified or defined by what is said in the body of the specification. (5) If a claim be clear, it is not to be made obscure because obscurities can be found in particular sentences in other parts of the document. But if an expression is not clear or is ambiguous, it is permissible to resort to the body of the specification to define or clarify the meaning of the words used in the claim. (6) A patent specification should be given a purposive construction rather than a purely literal one. Applying the guidelines provided by the foregoing authorities, the prima facie meaning of the phrase "further leaching processes" in step (v) is displaced by the dictionary provided by those parts of the specification to which I have drawn attention (EMI). A reading of the whole of the specification shows that the phrase is defined by those parts of the specification to which I have referred (Rosedale). The literal meaning of the phrase, which would put it in opposition to other parts of the specification and the examples, is displaced by a purposive construction, based on the specification as a whole, which shows that the draftsman did not treat two or more leaching processes as an essential requirement of the invention (Catnic). Turning to Sheppard J's rules, the verbal or grammatical question posed by the phrase "further leaching processes" can be answered by the ordinary rules of construction which require the specification to be read as a whole in a purposive and not a literal fashion (rules 1 and 6). Reading the phrase as not involving two or more distinct steps is a proper inference drawn from the claims themselves read in the light of the specification as a whole. It is thus not an impermissible confining of the scope of the claims by reference to limitations found in the body of the specification (rules 2 and 3). The meaning of the phrase is qualified or defined by what is said in the body of the specification (rule 4). Read in the light of those parts of the specification to which I have drawn attention, step (v) is not clear. Treating it as a general reference to a leaching process in accordance with all other parts of the specification does not make the step obscure (rule 5). For those reasons, on its true construction step (v) involves only one final leaching process, and RGC's contention that it will be easier to establish infringement under the amended specification than under the specification as it currently stands fails. SECTION 40 Under s 102(2)(b) an amendment is not allowable if as a result of the amendment the specification would not comply with s 40(2) or (3). RGC submits that in two respects s 40(3) is not satisfied. The first is that the word "titaniferous" in step (v) of claim 1 is not clear. As I understand the argument, it is that it is not clear whether the word has the same meaning as it has in step (i). Plainly it does have the same meaning. Before the amendment the phrase used in step (v) was "other impurity elements". As a matter of construction that is a reference to the impurities in the separate minor impurity bearing titaniferous phase referred to in step (i). The amendment simply makes express what was formerly implicit. It does not change the meaning of step (v). Accordingly, even assuming a lack of clarity in "titaniferous", that obscurity is not the result of the amendment. The second objection with respect to clarity is that the words "to form" in step (i) are unclear "because it is unclear whether this is to be tested in the kiln or upon cooling". Step (i) informs the reader that the carrying out of the reduction process will result in the formation of metallic iron, a major rutile phase and a separate minor impurity bearing titaniferous phase. Assuming that the preferred method of reduction is employed, the "formation" occurs in the kiln and not upon cooling. The cooling step is step (ii). In any event, if there is any lack of clarity, it is not something that would result from the amendment. Whatever lack of clarity inheres in the words "at a temperature of at least 900oC to form" resides as well in the words "under temperature conditions which promote the formation of" in the specification as it stands. The only s 40(2) matter pursued was the contention that step (i) does not define the invention. In RGC's outline of argument this was said to be because "a large number of variables need to be known to determine infringement". The submission was not otherwise expanded. I can only assume that conformably with par 1C3(a) of the Objections, the effect of the lack of clarity said to afflict step (i) is that claim 1 does not define the invention. On that view of the matter, the lack of definition is not a separate point. DISCRETION The Court has a discretion to refuse an amendment even though it is allowable under s 102. In Smith Kline & French Laboratories Ltd v Evans Medical Ltd [1989] FSR 561 at 569, Aldous J said: The discretion as to whether or not to allow amendment is a wide one and the cases illustrate some principles which are applicable to the present case. First, the onus to establish that amendment should be allowed is upon the patentee and full disclosure must be made of all relevant matters. If there is a failure to disclose all the relevant matters, amendment will be refused. Secondly, amendment will be allowed provided the amendments are permitted under the Act and no circumstances arise which would lead the court to refuse the amendment. Thirdly, it is in the public interest that amendment is sought promptly. Thus, in cases where a patentee delays for an unreasonable period before seeking amendment, it will not be allowed unless the patentee shows reasonable grounds for his delay. Such includes cases where a patentee believed that amendment was not necessary and had reasonable grounds for that belief. Fourthly, a patentee who seeks to obtain an unfair advantage from a patent, which he knows or should have known should be amended, will not be allowed to amend. Such a case is where a patentee threatens an infringer with his unamended patent after he knows or should have known of the need to amend. Fifthly, the court is concerned with the conduct of the patentee and not with the merit of the invention. This passage was cited with approval by the Court of Appeal in Hsiung's Patent [1992] RPC 497 at 522 and by Gummow J in Rescare Ltd v Anaesthetic Supplies Pty Ltd (Federal Court, 4 March 1993, unreported). In Smith Kline & French the patentees knew of the need to amend eight years before applying to amend. Aldous J refused leave on the ground that the delay was contrary to the public interest and that no good reason for the delay had been provided. In Hsiung leave to amend was refused because the court had been "left completely in the dark" as to whether there had been "culpable delay" between 1980, when the patentee became aware of the need to amend, and 1986 when application to amend was made. The patentee called no evidence as to what had happened in that period. In Bentley Engineering Co Ltd's Patent [1981] RPC 361 the patentees' original specification had a very broad claim for a knitted jumper, with sleeves that were integral to the body of the jumper and attached to it by armpit sutures. The patentees applied for a number of foreign patents corresponding to their British patent and in particular for a patent in the United States. Initially each foreign application also had a very broad claim similar to the original broad English claim. During the prosecution of the application in the United States a Swiss application in the name of Pfäuti was cited. The patentees then limited the original broad claim in the United States application so as to exclude the construction of the garment disclosed in Pfäuti. In order to avoid disclosing the Pfäuti document, the patentees waited for more than eight years before applying to amend the English claims. The Superintending Examiner refused leave to amend the English claim on the ground that the patentees had knowingly and deliberately sustained and maintained a claim of unjustifiable width in their English specification. The patentees' appeal was dismissed. Graham J found that there had been a clear anticipation of the patentees' original broad claim. The patentees were aware of it, and had to limit their claims in the United States. They had used their broad claim aganst the opponents to try to get a specific reference to their own British patent at a time when they knew that its breadth was unjustified. Dr Emmerson submitted that the Court should not approach the exercise of its discretion in a manner hostile or antipathetic to amendment. He drew attention to s 104 which deals with the Commissioner's power to amend. Amendments may be made for any purpose: sub‑s (1). Where leave to amend a complete specification is sought, the Commissioner must consider and deal with the request in accordance with the regulations: sub‑s (2). The Commissioner must not grant an amendment that is not allowable under s 102: sub‑s (5). Regulation 10.2 provides that for the purposes of s 104(2) the Commissioner must report on, amongst other things, whether any proposed amendment of a complete specification is not allowable under s 102. Regulation 10.5 requires the Commissioner to grant leave to amend if the report under reg 10.2 is not adverse to the patentee, and the Commissioner reasonably believes that the proposed amendments would remove all lawful grounds of objection to the complete specification. It was said for WIM that the Commissioner has no discretion under s 104 or under the regulations to refuse an amendment that satisfies s 102. The policy evinced by s 104 is that once s 102 is satisfied, amendments are to be allowed. It was submitted that although under s 105 the Court has a discretion to refuse an otherwise allowable amendment, it would be odd and anomalous if the Court were required to exercise its discretion in a spirit of antipathy towards the proposed amendments. I accept that the Court does not approach the exercise of its discretion in a manner hostile or antipathetic to amendment. Mr Catterns did not contend for such an approach. The discretion under s 105, like any other discretion, is to be exercised in the light of all relevant factors. The English cases highlight a number of considerations relevant to amendment applications. The Smith Kline & French "principles" seem to me, as they did to Gummow J in Rescare, to be appropriate guidelines. But they are only that. Since the matter is ultimately one of discretion, the "principles" should not be treated as fixed rules, to be applied inexorably to every case. They must be accommodated to the facts of the particular case. Thus, despite the language in which the principles are stated, a failure to make full disclosure of all relevant matters will not inevitably result in an exercise of the discretion adverse to the patentee. There may be circumstances which mitigate, explain or excuse some non‑disclosure. The non‑disclosure may be of some minor, though strictly relevant, matter. An adequate explanation may be provided for a disclosure which is not as complete as it might have been. An innocent non‑disclosure may have caused no harm. (a) Knowingly taking advantage of wide claims The first matter relied on by RGC as a discretionary consideration is that WIM has knowingly taken advantage of the excessively wide claims in the standard patent. WIM is said to have done this in two ways: by dispatching letters of demand to RGC, and by commencing infringement proceedings. For the reasons I have given when dealing with the s 102 issues, I do not regard the unamended claims which form the basis of the infringement proceeding as "excessively wide". In my view what Mr Catterns described as the two principal amendments ‑ 900oC in step (i) of claim 1 and "titaniferous" in step (v) ‑ do no more than make express that which is implicit in claim 1 as it stands. Mr Munt, WIM's patent attorney, gave evidence, which I accept, that he regarded these amendments as merely clarifying what was implicit in claim 1 as it stands. The fact that amendments are sought to steps (i) and (v) does not itself show that the claims are excessively wide. Although Mr Munt did not say that the amendments were made ex abundanti cautela, that is what his evidence amounted to. So I do not accept the starting point of the present submission. (b) Persistence in wide claims after advice Next it is claimed that WIM persisted in its wide claims until 4 July 1996, when it applied under s 105, notwithstanding that it had been advised in May and June 1994 that the claims should be amended. I refer to what I have said in par (a) about the width of the claims. Further, WIM did not sit idly by during that period. Shortly after receiving the advice it applied to amend under s 104. The amendments sought were not as extensive as those the subject of the present application, but the principal changes were to the same effect as those now sought under s 105. Thus claim 17 was almost the same as claim 1 would be after the s 105 amendments. Step (i) introduced the temperature of at least 900oC, and made clear that the impurities in the titaniferous phase are impurities that are in the titaniferous ore. Step (iii) referred to the cooled reduced product of step (ii) rather than of step (i). Step (iv) described the iron removed as "the readily removable form" of the iron. Step (vi) described the other impurity elements removed as "the readily removable form" of those elements. Step (v) referred to a leaching treatment with sulphuric and/or hydrochloric acid" rather than "further leaching processes", and it was made clear that the impurities that were to be converted were impurities in the impurity bearing titaniferous phase. Claims dealing with the mixing of an additive into the titaniferous material prior to step (i) were added. On 30 June 1994 the Commissioner granted leave to amend. On 14 July the particulars of the request for leave to amend were advertised in the Official Journal. In October RGC commenced opposition proceedings, the effect of which was that the amendments would not be allowed until the opposition was decided against RGC. See reg 10.6(3). Shortly thereafter WIM's solicitors advised it that the opposition proceedings could take several years to be determined by the Commissioner, that a decision in WIM's favour could be appealed to the Federal Court where there might be further delays, and that there might be an appeal to the Full Court. WIM was advised that the s 104 application could take between five and seven years finally to be determined, and that that would result in substantial delay to the infringement proceeding (if the standard patent were to be included), and RGC's SREP pilot operations might thus be outside the six year limitation period prescribed by s 120(4). WIM then instructed its solicitors to amend the proceedings to allege infringement of the standard patent, and to apply to amend the standard patent under s 105. The instructions were to make the amendment application immediately after RGC had provided further and better particulars of invalidity, so that if any additional grounds of invalidity capable of being remedied by amendment were raised, appropriate amendments could be fashioned. As a result of those instructions the proceedings were amended on 30 November 1994. On 13 January 1995 RGC's Statement of Grounds and Particulars of Opposition was served. On 20 February its Amended Particulars of Grounds of Invalidity were served. On 27 February WIM's request for further and better particulars of the Amended Particulars of Grounds of Invalidity was served. On 10 March WIM's solicitors inquired of RGC's solicitors when the further particulars would be available. On 15 March Heerey J ordered that they be provided on or before 30 March. They were provided on 13 April. WIM's solicitors were not satisfied with the further particulars, and when RGC refused to amplify them, issued a notice of motion seeking further and better particulars. The motion was heard on 20 and 21 July, and judgment was given on 6 March 1996. WIM was not satisfied with the judgment, and on 13 March filed an application for leave to appeal. On 17 May WIM's solicitors gave RGC's solicitors notice of its proposed s 105 amendments. Correspondence ensued between then and 3 July, and on 4 July WIM applied to amend under s 105. The sensible approach adopted by WIM of awaiting full particulars of invalidity before formulating the amendments unravelled when it thought the particulars provided by RGC were inadequate. There was a delay of more than eight months between the hearing of the motion and its disposition. And then there was an application for leave to appeal. In retrospect, the matter might have been approached differently. However, mere delay is not of itself necessarily sufficient to justify an exercise of discretion adverse to a patentee. Although the delay here was considerable, it was a consequence of an initially sensible decision to await further particulars, and unlike the position in Smith Kline & French and Hsuing, the delay was fully explained. But for the perceived inadequacy of the particulars and the eight month delay in the disposal of the motion, the preferred approach would have enabled the s 105 application to have been made by mid‑1995. The delay here is not culpable. There is no evidence that it caused detriment to RGC or to the general public. Nor is there any evidence that the delay was a deliberate ploy designed to gain some illicit advantage. Cf Matbro Ltd v Michigan (GB) Ltd [1973] RPC 823 at 833‑834 and Bentley Engineering. Indeed, it was in part entirely beyond WIM's control. (c) Refusal to specify purpose of amendments In its statement of the grounds relied on for the proposed amended claims WIM said that the amendments were sought more clearly to define the invention (par 2(a)), to narrow the issues in dispute by removing grounds of objection to validity alleged by RGC (par 2(b)) and to correct a clerical error (par 2(c)). In par 2(iii) it was said that the clearer definition and the removal of grounds of objection were to be achieved by expressly defining twenty‑one listed matters. RGC asked WIM to specify the amendments directed to narrowing the issues in dispute by removing grounds of objection to validity, and the grounds of objection to validity which were overcome by the proposed amendments. WIM responded by saying that the narrowing process applied to each of the proposed amendments listed in par 2(iii) of its statement of grounds, and that the allegations of invalidity referred to were those set out in pars 9 to 13 of RGC's Amended Particulars of Grounds of Invalidity. That seems to me to be a satisfactory response. The request was in general terms and did not invite a particularised answer. RGC did not at the time complain that WIM's statement did not comply with the order pursuant to which it was made. I do not accept RGC's claim that WIM's response was a refusal "to specify in any meaningful way what is the purpose of any of the amendments". WIM was not asked to identify its purpose in seeking to amend. (d) Petty patent The next discretionary consideration relied on by RGC is expressed as follows in the Objections: "as a result of the amendment, if granted, the patent would claim an invention the same as the petty patent and is made by the same inventors and each of the claims of the relative specifications has the same priority date". This appears to pray in aid s 64(2). Whether s 64(2) applies, so that "a patent cannot be granted on the application", may have to be resolved in the substantive part of the proceeding. But it is not a matter relevant to the discretion to amend. In oral argument the matter was put differently. It was said that the petty patent, which has now expired, used the phrases "at a temperature of at least 900oC to form" in step (i), and "impurity elements in the minor impurity bearing titaniferous phase" in step (iv). It was said that the petty patent having expired, WIM wants to put these matters into the standard patent. Counsel for RGC submitted that while what WIM has done is "a perfectly legitimate practice" that has given it a benefit which it is entitled to have, "it casts a light on the amendments, and ought to have been brought before the court". The matter was not further developed. Counsel conceded that this was not a "knock‑out point", and it is not a factor that in my view points to an exercise of discretion adverse to WIM. (e) Catching infringer The last of the pleaded discretionary considerations is that the proposed amendments are sought for the purpose of framing a claim that will cover RGC's SREP process. In my view there is nothing exceptionable or reprehensible in that. A patentee who proposes amendments with a view on the one hand to catching an infringement and on the other to steering clear of the prior art is not acting in a blameworthy manner. That is what amending parties always try to do. See Mabuchi Motor KK's Patent [1996] RPC 387 at 400. (f) Failure to disclose other applications (1) International phase amendments Although it is not pleaded, RGC contended that WIM had not satisfactorily explained its failure to disclose international phase amendments made in 1992. These are the amendments that resulted in the specification assuming its present form. They include the amendments I have described in pars (a), (d), (e), (g) and part of par (c) under the heading Specification as Accepted. It was pointed out that in his affidavit setting out the history of the application for the standard patent, Mr Hamer jumps from the lodging of the standard patent application in March 1991 to a request in July 1992 that the application enter the national phase in Australia. In between those events lay the international phase amendments. It was submitted for RGC that the Court should have been told that the 1992 amendments were designed to get over the same prior art that WIM is still trying to avoid by the amendments now sought. I do not think the reasons for the 1992 amendments are relevant to the discretion to permit amendments to the specification as it now stands as a result of the 1992 amendments. Mr Hamer was cross‑examined about the omission from his affidavit of any mention of the 1992 amendments. His evidence, which I accept, was that his affidavit does not mention the international amendments because he was not aware that they had been made. The file he obtained in order to draft his affidavit did not contain the international phase documents. Although these documents were voluntarily disclosed in the course of discovery in May this year, Mr Hamer had no involvement with that process because he was overseas at the time. (2) United States application In September 1992 WIM filed a specification in the United States Patent and Trademark Office. The specification was in essentially the same form as that filed in Australia in March 1991. In the United States, the first examiner's report of October 1993 rejected the claims on the ground, amongst others, that the invention had been anticipated by United States Patent 4,097,594 (Auger et al) published in 1978 ("Auger"). In April 1994 WIM prepared various amendments some of which had the effect of bringing the specification into the form of the Australian specification as it now stands. There was however a new claim 17 which stipulated a reduction temperature of at least 900oC. These amendments were rejected in July 1994 on the ground of anticipation by Auger and "Becher et al". ("Becher et al" is not specifically identified, but is probably Becher et al, A New Process for Upgrading Ilmenite Mineral Sands, Australian Institute of Mining Proceedings, 6 1965, 21‑43 ("Becher")). In September two inventions were proposed with a view to avoiding prior art. The first involved subjecting the product from which iron has been removed to acid leaching using sulphuric acid having a concentration of at least 20%. The second involved (a) conducting the reduction step at a maximum temperature of 900oC to 1100oC for a time insufficient to complete conversion of impurity iron present in the ore or concentrate to metallic iron, or (b) conducting the reduction at a maximum temperature of 900oC to 1200oC in the presence of an additive to limit the formation of M3O5 while promoting the formation of a more easily leachable titaniferous phase. The proposals were accepted by the Office, and after appropriate amendments were fashioned, the United States Patent was granted in June 1995. It was contended for RGC that the discretion should be exercised against allowing the amendments because of WIM's lack of candour in failing to refer to the United States application where, it was said, similar amendments were made to overcome prior art. Two of the four amendments obtained in the United States have not been sought in Australia. The first is that the reduction of the titaniferous ore must occur "for a time insufficient to complete conversion of impurity iron present". The second is that the product from which the iron has been removed is subjected to leaching, utilising sulphuric acid having a concentration "of at least about 20% ...". The third United States amendment is that the reduction take place at a maximum temperature of 900‑1200oC. Claim 10 of the Australian specification as it stands has this temperature range. The amendment sought replaces that range with "temperature ... less than 1200oC". As a matter of construction "less than 1200oC" means "between 900 oC and 1200 oC". See step (i) of claim 1. There is thus no substantive change in this respect. Accordingly, none of these three American amendments is a "relevant matter" for the purposes of the current application. Cf Smith Kline & French at 569. The fourth amendment obtained in the United States is that an additive "be mixed into the titaniferous ore to encourage the formation of the separate minor impurity bearing titaniferous phase". The same amendment is sought here. The United States examiner's report approving the amendments reveals that their purpose was to overcome prior art - "the prior art does not teach promotion of formation of a leachable titaniferous phase using an additive". Accordingly, all that disclosure of WIM's American experience would have shown that is relevant to the present application, is that in late 1994 and early 1995 WIM was concerned to avoid prior art by way of the same "additive" amendment that is now sought to be made to the Australian specification. But that disclosure of itself exposes nothing of a disqualifying nature. The contrast between the present case and Bentley Engineering is clear. There the Pfäuti patent was cited in the United States in June 1967. It was an impediment to the broad claim in the United States proceeding, which the patentees narrowed to avoid the problem. But it was eight years before they sought to amend the broad claim in Britain, and they did not then disclose Pfäuti. The opponents did. Exposure of the United States experience disclosed that the patentees had waited for eight years before seeking to amend their British claims in the knowledge derived from the American experience that the claims were too wide. The exposure thus showed up a case of serious delay coupled with reliance on a claim known to be unjustifiably broad. And when they did seek to amend, the patentees did not disclose the troublesome prior art. In the present case disclosure of the United States events would have shown the Court that WIM discovered between October 1993 and July 1994 that the prior art necessitated amendments to the United States specification, only one of which was relevant to the amendments sought to the Australian specification. The amendments were allowed in early 1995. WIM did not apply to amend under s 105 until two years later. But it did not lie by while asserting its existing claims. In June 1994, while the "negotiations" with the United States Office were still proceeding, it sought and obtained leave to make amendments under s 104 which were designed to overcome prior art already disclosed in the specification as it stands. In those circumstances, WIM has not nursed a prior art problem in an awareness of experience derived from a foreign application, as did the patentees in Bentley Engineering. Unlike the patentee in Hsuing, who waited six years after becoming aware of the need to amend before applying, and even then left the court "in the dark" as to whether the delay was culpable, WIM made its s 104 application while the American "negotiations" were still progressing. And the delay between making that application and the current application is fully explained by Mr Hamer. Smith Kline & French (where the patentee did not apply until eight years after discovering the need to amend, and even then did not explain the delay) is distinguishable for the same reasons. For the foregoing reasons I do not regard WIM's failure to disclose the United States experience in the material filed in support of the motion as a disqualifying consideration. The experience was of course fully explored in the cross‑examination of Mr Munt and Mr Hamer. (3) European application In October 1991 WIM filed a specification in the European Patent Office. The specification was not in evidence. The specification was rejected in June 1995. Amendments were proposed in March 1996 essentially along the lines of the s 104 amendments. This suggests that the specification as lodged was in essentially the same form as that lodged in Australia in March 1991. The amendments were rejected in July. Further amendments were propounded in February 1997 essentially along the lines of the s 105 amendments. They too were rejected. Discussions are continuing. RGC submits that WIM's failure to disclose the European application should lead me to refuse the amendments in the exercise of my discretion. I do not agree. Amendments were first proposed in Europe in March 1996, and these and other amendments have been under consideration since then. They were preceded by the s 104 amendments and are substantially contemporaneous with the s 105 amendments now sought. In those circumstances disclosure of the European events would not have shown a case of delay or any nursing of a prior art problem. (g) Failure to disclose true purposes (i) to catch RGC In its statement of grounds for the proposed amended claims WIM said that the amendments were sought to define more clearly its invention, to narrow the issues in dispute by removing grounds of objection to validity, and to correct a clerical error. RGC contended that this was an inadequate disclosure of the purpose behind proposed claims 4 and 5, which was to cover the SREP process ‑ to catch RGC as an infringer. WIM had not put the full story before the Court. Mr Hamer's affidavit explaining the amendments said only that proposed claims 4 and 5 "relate to the use of additives in the process", and he referred to that part of the specification which mentioned the optional additives. It was said that Mr Munt's affidavit throws no more light on the real reason behind the desire to insert claims 4 and 5. It is true that WIM's statement of grounds for the amendments and the affidavits relied on in support of the motion to amend could have been more forthcoming on the point. But I am satisfied that in substance the purpose of the amendment has been sufficiently disclosed. In his affidavit Mr Hamer says that WIM's officers became aware in 1993 of RGC's SREP process, and suspected that it was the same as the process claimed by WIM's patent. In April 1994 WIM's Dr Hollitt attended a conference in Berlin at which an RGC employee delivered a paper entitled "The Reduction of Radionuclides in Titaniferous Feed Stocks", a copy of which was exhibited to Mr Hamer's affidavit. The paper contained these passages describing the SREP process: The initial work at the CSIRO in Port Melbourne concentrated on the addition of chemical reagents to ilmenite .... It was found during the research programme at the CSIRO (Port Melbourne) that pretreatment of the mineral with a flux prior to heat treatment lowers the temperature at which the radiation rich phase is formed, and improves the subsequent solubility of that phase in the leaching process to the point where relatively dilute acids can be employed for dissolution. A number of fluxes were found to be satisfactory for use with heat treatment of ilmenite and synthetic rutile. Some of the fluxes that were trialed include sodium di‑hydrogen phosphate, borates including borax, lithium minerals, and some silicates. However for commercial reasons, significant time was devoted to the development of a fluxing heat‑treatment system that would be compatible with the existing Becher process. The SREP team has been successful in developing a process that is entirely compatible with the current kilning/aeration/acid leaching process as practised at RGC's sites. In addition to the radioactive elements, the fluxed phase also acts as a sink for other impurities namely iron, aluminium, silica, manganese and to some extent magnesium .... It is apparent from this description that an important feature of the SREP process is the addition to the ilmenite of a flux ‑ a substance introduced in order to promote fluidity and remove objectionable impurities from the ilmenite. In an exhibit to another affidavit sworn by Mr Hamer (which is an exhibit to the affidavit referred to above) he describes his inspection of RGC's Narngulu C plant in May 1995. He says that the equipment used had been constructed and in operation for some time and had not been constructed solely for the purpose of the SREP trial. However there had been some important temporary modifications to the original "plant configuration", including "the addition of a non‑sulphur additive to the kiln". The amendments sought by WIM under s 104 contained an "additive" claim. RGC's statement of grounds of opposition to those amendments is an exhibit to Mr Hamer's affidavit. One of the grounds is that the amendments should be refused in the exercise of the Commissioner's discretion because the amendments are sought not in order to claim or define any invention known to WIM but for the purpose of trying to claim or to frame a claim that would cover RGC's SREP process. It is thus clear from the material filed in support of the motion that · the SREP process involves the mixing of an additive into the ilmenite prior to the reduction phase · the specification as it stands does not claim a process which includes such an additive · RGC had opposed the s 104 amendments on the ground (amongst others) that the amendments were sought for the purpose of catching its SREP process · WIM desires to amend the specification by inserting an additive claim. Had I assessed the material filed in support of the motion at the time it was filed, (ie without the benefit of cross‑examination and submissions), I would have been in no doubt that WIM wished to add claims 4 and 5 in order to catch the SREP process. As I have said, that purpose could have been spelt out in one of the affidavits. But it was apparent from the exhibits to Mr Hamer's affidavit. I entirely acquit Mr Hamer and Mr Munt, who were both extensively cross‑examined, of any attempt to hide that purpose from the Court. Since the purpose is apparent from the material filed, it cannot be said that WIM has failed to place the whole story before the Court. (ii) to avoid prior art RGC also complains that WIM has not disclosed another purpose behind the proposed amendments, namely the avoidance of prior art. As I have said under the preceding heading, one of the reasons advanced by WIM in its statement of grounds for the amendments was to narrow the issues by removing grounds of objection to validity alleged by RGC. One of those grounds is that the alleged invention is not novel when compared with the prior art base. The prior art relied on by RGC includes Australian Patent 516,155 (Hockin and Rolfe) published on 21 May 1981, and Auger. In Mr Munt's affidavit in support of the motion he says that in January 1994 he received RGC's statement of grounds of opposition which asserts, amongst other things, lack of novelty. The particulars list a large number of items of prior art. Mr Munt considered the grounds and concluded that they did not raise any issue as to the validity of the claims which was likely to succeed. It was his view that the claims, as accepted, were valid. After the standard patent was sealed, Mr Munt conferred with senior counsel. He formed the view that there was a "potential argument" that the impurities leached in step (v) of claim 1 might not be impurities from the impurity bearing titaniferous phase formed in step 1. He did not think the argument was sound, because he regarded it as implicit in the words in step (v) ‑ "other impurity elements" ‑ that the impurities were impurities from the impurity bearing titaniferous phase formed in step (i). Nevertheless, following the conference he considered that the matter should be made clear by amendment. He then drafted the s 104 amendments. Later he drafted the s 105 amendments. In doing so he revised the s 104 amendments to deal with the same issues he had considered in relation to the s 104 stage in what he thought was "better language". He included additional, progressively narrower, subsidiary claims which he derived from, and considered were fairly based on, matter in the complete specification. He divided claim 2 into two alternative subsidiary claims. In the course of a lengthy cross‑examination Mr Munt was pressed to accept that his affidavit does not disclose that the purpose of the amendments is to deal with various pieces of prior art. He maintained that what he had said in his affidavit about the subsidiary claims was correct, and that it was not his intention in drafting them to distinguish the prior art. He agreed, however, that a consequence of including a larger number of claims is that a patentee has a better basis on which to distinguish prior art. I accept Mr Munt's account of his intentions. He gave his evidence frankly and directly, with no attempt at evasion. He readily agreed with certain suggestions put to him by Mr Catterns that were prima facie against WIM's interests. In relation to the amendment to step (i) inserting the phrase "at a temperature of at least 900oC to form", Mr Munt agreed that part of the reason for the insertion was to distinguish or further distinguish art of the Auger type. But he maintained that the temperature limitation is implicit in claim 1 as it stands. Pressed as to the existence of a dual purpose ‑ to improve expression and clarity and remove ambiguity on the one hand and to get over prior art on the other ‑ Mr Munt said he had wanted to make more explicit features he thought were implicit and which distinguished the invention from prior art. Asked about the amendment to step (v) inserting "said other impurity elements being impurities in the separate minor impurity bearing titaniferous phase", Mr Munt agreed that his affidavit does not mention that the change was made in order to avoid the modified Becher process (Hockin and Rolfe). But he said that that is implicit in that part of the affidavit in which he had said that if he were wrong in his understanding of the phrase "other impurity elements", so that it picks up impurities other than those in the impurity bearing titaniferous phase referred to in step (i), then the added words would avoid the modified Becher process. Mr Munt also rejected the suggestion that claim 7 is intended to distinguish the Murso process. He agreed that it might be a consequence of the new claim that the Murso process would be distinguished, but said that that was not in his mind when he drafted the claim. He declined to accept the suggestion that he had split claim 2 into claims 2 and 3 because of issues of invalidity (ie to avoid the modified Becher process). He said it is better to have a separate claim for each alternative in the existing claim. I accept his evidence on these matters. What emerges from Mr Munt's evidence is that he was of the opinion that the 900oC insertion in step (i) and the definition in step (v) are implicit in claim 1 as it stands. It will be apparent from what I have said when dealing with the s 102 issues that I share that view. In any event, it is a view that Mr Munt could reasonably have held, and I accept that he held it. He regarded the relevant prior art, with which he was familiar, as already distinguished by what was in the claims. What he was doing was making explicit that which was implicit. Although in his affidavit Mr Munt could have been more forthcoming about his "dual purpose" (in the sense explained by him) in making the two amendments, in exercising my discretion I have weighed in the balance the following additional considerations: · RGC's objection to validity (which is exhibited to Mr Hamer's affidavit) disclosed that RGC contended that the invention was not novel because of prior art including Auger and the modified Becher process · WIM's statement of grounds relied on for the proposed amended claims said that the amendments were sought to narrow the issues in dispute by removing grounds of objection to validity urged by RGC · Mr Munt considered the grounds of opposition and concluded that they did not raise any issue as to validity which was likely to succeed · Later Mr Munt formed the view that there was an argument that the impurities leached in step (v) might not be impurities from the impurity bearing titaniferous phase formed in step (i); but he did not think this view was sound, since he regarded it as implicit in step (v) as it stands that the impurities referred to are those in the phase referred to in step (i) · Mr Munt regarded the 900oC amendment to step (i) as making explicit that which is implicit · Despite his views on the construction of steps (i) and (v), he decided to seek the amendments to remove any doubts · Although in each case he had another purpose, namely more clearly to avoid Auger by one amendment and the modified Becher process by the other than he thought he had already done, in neither case was that his dominant purpose · Mr Munt was quite open and frank about the existence of the dual purpose (in the sense explained by him). He did not fail to disclose it in his affidavit from any base or ulterior purpose. Taking all these considerations into account, I have concluded that Mr Munt's failure to disclose that one of his purposes was more clearly to avoid the Becher and Auger prior art than he thought he had already done, is not of such a character as to disentitle WIM to the amendments which are otherwise open. (h) Conclusion Having considered all the matters advanced by RGC, both individually and cumulatively, I am not persuaded that I should, in the exercise of my discretion, refuse to allow the amendments. ORDER I will direct the amendment of the complete specification in accordance with the schedule to the notice of motion. I will hear counsel on the question of costs.