No breach of s 86(1) established
67I find that Mr Lester has not established that Ashton has harmed either the grinding grooves or any other Aboriginal object at the Waterhole site, in breach of s 86(1) of the Parks Act.
68Although Mr Lester pleaded that harm had been caused to any grinding grooves in general, no evidence of harm was adduced in relation to grinding grooves at the Waterhole site other than the grinding grooves on the outcrop, referred to as GG1.
69The parties' geological experts agreed in their joint expert report that there are physical signs of deterioration on the outcrop surface immediately to the east-southeast of grinding groove site GG1. They used the neutral word 'feature' to refer to this area of surface deterioration. The experts agreed that there was no other evidence of subsidence elsewhere on the outcrop (para 3.2.1 of the joint expert report).
70The experts differed, however, as to when this feature at GG1 may have occurred and what might have caused it (para 3.2.1).
71Mr Wesley, a mining engineer and the General Manager of Ashton, gave evidence concerning the longwall mining near and the first workings underneath the Waterhole site. Mr Wesley said that the Waterhole site is located 144m to the north of Longwall Panel 4, the closest longwall panel to the Waterhole site, and that no longwall mining has been carried out, or is proposed to be carried out, under the Waterhole site. Mr Wesley said that mine roadways, known as first workings, are situated beneath the Waterhole site, but these do not cause subsidence (paras 24 and 25 of Mr Wesley's affidavit of 14 May 2012).
72Mr Daigle, a geologist called by Ashton, described the feature on the outcrop as surface spall and fretting of edges. Mr Daigle was of the opinion that these are natural features and are consistent with a natural deterioration of this type of outcrop. He expressed the opinion that there had been no change during the period 2008 to 2011 (para 3.2.1 of the joint expert report).
73Mr Daigle's opinions were developed extensively in his expert report annexed to his affidavit of 18 May 2012 and in his oral evidence given to the Court.
74Mr Daigle inspected the grinding groove site GG1 in April 2011 and completed a survey on 27 July 2011. Mr Daigle said that during both of these inspections he did not observe any signs of mine subsidence at the grinding groove site GG1. If there had been subsidence, he said he would have expected to observe features such as a trend of linear surface cracks and settling of adjacent soil but none of these features of mine subsidence was evident.
75Mr Daigle again inspected the grinding groove site GG1 on 26 April 2012. Again, Mr Daigle said he did not observe any signs of mine subsidence such as a trend of linear surface cracks or settling of adjacent soil. Mr Daigle inspected the outcrop surface, mapped the distribution of rock types and determined the geology of the site.
76Mr Daigle said:
The grinding grooves are located on an exposed lens of medium to course grain sandstone separating a bed of pebble grit from an underlying thick massive bed of pebble to cobble conglomerate.
...
The grit bed and the pebble cobble conglomerate layers exhibit thick exfoliation joint separated layers following the surface contour. A finer layering is present in the sandstone lens hosting the grinding groove site GG1, this layering is a skin spall and is typically less than 10mm thick. In places this spall is broken and fresher rock is exposed. (page 5 of expert report attached to Mr Daigle's affidavit of 18 May 2012).
77Mr Daigle arranged for digital photography of the grinding grooves to provide 3D photogrammetric analysis, a record of the condition of the site, and to demonstrate the amount of physical change present compared to previous images of the site. Mr Daigle reported on his 3D photogrammetric investigation as follows:
Digital imagery shown in Figure 3 demonstrates the diagnostic shape of a grinding groove as a consistent cross section along the trace of the groove which is also shown as a consistent feature when shown as a longitudinal section. The thin sandstone lens hosting the features shows weathering is intense and a skin spall has developed where mineral leaching and re-deposition by cycles of wetting and drying of the stone has occurred over time. In places the skin spall has separated and lifted away from the outcrop surface forming thin fragile sheets composed of the parent sandstone. Sections of this thin sheet have broken off and have disintegrated. The photo-imagery completed shows the areas where spalled skin is absent (Figure 4). This is considered a natural process, where weathered stone is gradually broken down by the chemical and mechanicals forces of nature. Evidence of the wetting cycle is confirmed in the surveying completed which demonstrated high water levels will engulf the grinding groove site (Figure 2). The sandstone comprising the grinding groove site is susceptible to forming spall and such sites are at risk of weathering away over time through this natural process, especially sites which undergo more intense or frequent cycles of wetting and drying.
Spall is where the outcrop surface forms sheets of the parent rock material, it is an exfoliation of the skin of the rock surface. Several forces and rock characteristics act together to create this effect, the thickness and character of the spall is mainly resulting from the combined effects of weathering and the stresses present in the rock. The weathering acts to degrade the rock surface and allows water and air to leach minerals from the rock creating a surface parallel zoning within the rock mass. Inherent stresses within the rock mass then act to cause the surface zoning to form a parting parallel to the rock mass surface. The resulting surface parallel sheet is the spall from the outcrop, the thickness of the spall is usually a function of the rock grain size, hence finer grained material such as sandstone can have very thin spall sheets and coarser materials such as conglomerate will produce much thicker spall sheets. (page 5 of expert report attached to Mr Daigle's affidavit of 18 May 2012).
78Mr Daigle also said that:
Viewing of the colour enhanced image (Figure 3) clearly demonstrated the location of recent spalling and when compared to images of the outcrop taken in 2009, no new spalling was noted adjacent to the GG1 grinding grooves. (page 8 of expert report attached to Mr Daigle's affidavit of 18 May 2012).
79Mr Daigle concluded:
Based upon the digital imagery and mapping I have prepared, in my view, there has been no subsidence from mining at the Waterhole Grinding Groove Site GG1.
During each of my site inspections, I have observed no signs of mine subsidence such as trends of surface cracking or soil settle at the Waterhole Grinding Groove Site GG1.
In my opinion, the analysis of photos and subsidence data scientifically establishes that there has been no mine subsidence at the Waterhole Grinding Groove Site GG1.
It is clear that the Waterhole Grinding Groove Site GG1 undergoes constant active natural erosion processes. The visible cracking of the sandstone upon which the grinding grooves is located is caused by natural erosion, the cycle of wetting and drying and other natural causes such as Macropods (kangaroos). Natural weathering of the skin of the sandstone rock has and continues to occur.
These processes are completely distinguishable from fractures induced by mining subsidence. The expected type of fractures over subsided ground are fresh breaks and are long somewhat linear tension openings which are penetrative from the surface with downward depth, none of these were observed at the site nor were any anticipated.
In my opinion there has been no mining subsidence at the Waterhole Grinding Groove Site GGA caused by underground longwall mining at the Ashton Coal Project. (pages 8-9 of expert report attached to Mr Daigle's affidavit of 18 May 2012).
80Mr Daigle's oral evidence corroborated these opinions.
81Dr Mills, a geotechnical engineer called by Ashton, as well as Mr Daigle, stated that, based on their subsidence experience and the nature of subsidence monitoring data available, subsidence movements sufficient to cause perceptible rock disturbance at the GG1 site have not occurred (para 3.2.2 of the joint expert report).
82Dr Mills' geotechnical engineering firm, SCT Operations Pty Ltd, was engaged by Ashton in July 2009, prior to longwall mining taking place in Longwall 4 nearest to the Waterhole grinding groove site GG1, to provide its expert opinion on the potential for subsidence to impact the site. Dr Mills prepared the expert report. He inspected, mapped and photographed the grinding groove site. Dr Mills stated in his 28 July 2009 report:
The grinding groove site is located approximately 250m north of the northern end of Longwall 4. The overburden depth in this area is approximately 80m, so the site is located approximately 3.1 times overburden depth from the nearest longwall mining activity. At this distance there is no credible mechanism to cause perceptible impact.
Previous subsidence monitoring indicates that horizontal movements are limited to mainly within the longwall panels at Ashton Mine and reduce to less than survey tolerance (20mm) within about 50-100m of the goaf edge. At 250m distance, there is considered to be no potential for perceptible impacts. The location of the site adjacent to Bowmans Creek adds further protection, because there is no potential to generate horizontal strains on the rock surface with a free surface nearby.
83Dr Mills subsequently visited the Waterhole site on 14 June 2012 and inspected the grinding grooves located on the outcrop (GG1). In his expert report annexed to his affidavit of 19 June 2012, Dr Mills concludes that:
I am of the opinion that there have been no significant ground movements at the Waterhole site generally and any small movements that may have occurred are likely to be of a general body nature (everything moves together). If these low level movements were to have occurred, they would be of a magnitude that would not be perceptible to the eye or cause perceptible physical impacts because they are well below the tolerance of the ground to such movements. (Section 2.3 of Dr Mills' expert report).
84Dr Mills' reasoning for this conclusion is to the same effect as that given in his report in 2009. In essence, the outcrop on which the grinding grooves are located is situated sufficiently far away from the end of the closest longwall, Longwall 4, that the vertical subsidence, tilt and horizontal strain caused by underground longwall mining are of such a small magnitude that they would not be perceptible to the eye or cause perceptible physical impacts, being within the tolerance of the type of ground at the Waterhole site to such movements. Dr Mills expresses this reasoning as follows:
In my opinion, the Waterhole site is of a character that is likely to be generally tolerant of low level mining induced ground movements should any occur. I consider it unlikely that ground strains of less than about 4-5mm/m would be perceptible to the eye in the type of terrain that makes up the broad area of the Waterhole site.
The Waterhole site is located in an area from about 145m to 300m north of the end of Longwall 4 (Annexure BW-6). The overburden depth to the Pikes Gully Seam ranges approximately 70m to 85m at the northern end of Longwall 4. Subsidence monitoring on subsidence line CL2 (the longitudinal subsidence line at the northern end of Longwall 4) indicates that the vertical subsidence directly above the northern end of Longwall 4 (finish line goaf edge) is less than 20mm (Figure 6 in Annexure MC-5). Maximum ground tilt at the finish line is less than 3mm/m, horizontal movements are approximately 25mm in an eastward direction, and horizontal strains in a direction along the subsidence line are less than 1mm/m. Pegs are spaced at nominal 5m centres. A correction for standard peg spacing of 1/20th depth or approximately 4m increases the tilts and strains by 25%, but they remain small. (Section 2.3 of Dr Mills' expert report dated 19 June 2012).
85Dr Mills' oral evidence corroborated these opinions.
86In response to the evidence of Mr Wesley, Mr Daigle and Dr Mills, Mr Lester called Dr Cotter, a geoarcheologist, and Ms Hellwig, a geologist.
87Dr Cotter described the feature on the surface of the outcrop to the east-southeast of the grinding grooves (GG1) as 'exfoliation and surficial cracking' or 'surficial cracking and micro-fracturing' (para 42 of Dr Cotter's affidavit of 25 January 2012 and para 3.2.1 of the joint expert report). Dr Cotter stated that she had made a brief comparison of the photographic and documentary evidence and had inspected the grinding groove on 7 December 2011. Based on this analysis, Dr Cotter considered that '[s]ome exfoliation has been apparent since 2008 however surficial cracking appears to have increased over time and perhaps markedly during the period between 2010 and 2011' (para 42 of Dr Cotter's affidavit of 25 January 2012). Dr Cotter said in the joint expert report that she was of the view that there had been a change and increased cracking between 2008 and 2011 (para 3.2.3 of the joint expert report).
88However, Dr Cotter stated that it was not possible, from the collection of photographs between 2008 to 2012, to say categorically what are the causes of the physical deterioration or when it occurred (para 3.2.1 of the joint expert report), that is to say, whether it is of natural origin or induced by mine subsidence (para 42 of Dr Cotter's affidavit of 25 January 2012). Dr Cotter considered that it is 'a small possibility that some of the changes are associated with first workings and perhaps the approach of Longwall 4, but without baseline data, it is not possible to tell.' (para 3.2.2 of the joint expert report).
89Ms Hellwig did not visit any of the sites at the Ashton coal mining project, including the Waterhole site. Essentially, Ms Hellwig's evidence was directed to not ruling out the possibility that underground longwall mining or first workings could have had an impact on the grinding grooves at the Waterhole site. Thus, Ms Hellwig said 'there has been no continuity of monitoring of the site which makes it difficult for any expert opinion to be categorical'; 'insufficient documentation of potential surface changes within the broader Waterhole site impacted on the ability of the experts to make fully informed conclusions regarding the nature and character of the feature observed at GG1'; and 'a lack of evidence for subsidence induced changes elsewhere within the Waterhole site should in no way be used to infer or substantiate the existence or otherwise of subsidence induced changes at GG1'. (para 3.2.2 of the joint expert report).
90In a like vein, Ms Hellwig responded to Mr Wesley's opinion that first workings at the Ashton coal mining project do not cause subsidence, by saying that '[w]hilst this assumption is typical in recent years in NSW mines, it cannot be claimed with absolute certainty' (para 36 of Ms Hellwig's affidavit of 12 June 2012). She referred to instances of panel sag in first workings that had occurred elsewhere in NSW between 1988 to 1992 to support her view that Mr Wesley's opinion is not certain.
91Ms Hellwig responded to Mr Daigle's opinion that any subsidence from mining of Longwall Panel 4 would be so small as not to appear as surface expression, by saying that it could be subsurface and virtually undetectable and yet impact sensitive structures such as the Waterhole site. Hence, Ms Hellwig considered that assumptions in relation to the potential of mine subsidence at the Waterhole site cannot be made with certainty (para 37 of Ms Hellwig's affidavit of 12 June 2012).
92Ms Hellwig responded to Dr Mills' report in 2009 predicting that there would be no physical impacts on the grinding grooves by undertaking longwall mining of Longwall Panel 4, by saying that without further information she is unable to determine the impact longwall mining-induced movement may have on surrounding subsidence expression and potential surface erosion structures. Hence Ms Hellwig considered there still was a possibility of surface and subsurface movement which may affect surface sites such as the GG1 site (paras 41 and 42 of Ms Hellwig's affidavit of 12 June 2012).
93Ms Hellwig stated that '[it] may be the case that sub-surface fracturing from the end of Longwall 4 and/or the first workings impacts the entire Waterhole site' (para 43) and that 'the Waterhole site damage ... could be related to subsidence from either the first workings, or Longwall 4' (para 45 of Ms Hellwig's affidavit of 12 June 2012).
94I accept the evidence of Mr Wesley, Mr Daigle and Dr Mills, and reject the evidence of Dr Cotter and Ms Hellwig to the extent it is to the contrary, that the feature on the outcrop surface to the east-southeast of the grinding grooves GG1 is not caused by subsidence from Ashton's longwall mining or first workings, but rather from natural forces. In particular, I accept the evidence of Mr Wesley, Mr Daigle and Dr Mills that:
(a)the first workings, being mine roadways, underneath the Waterhole site have not caused subsidence; and
(b)the end of Longwall Panel 4 is sufficiently distant from the outcrop on which the grinding grooves GG1 are located that any subsidence, tilt or strain caused by longwall mining would have been of such a small magnitude as not to cause perceptible rock disturbance at the grinding grooves.
95I accept the evidence of Mr Daigle, based on his inspection of the outcrop surface, mapping of rock types, determination of the geology of the site, comparison of photographs between 2008 and 2009 and 3D photogrammetric analysis, that there has been no mine subsidence at the grinding grooves site GG1 and no new spalling has occurred adjacent to the grinding grooves after completion of longwall mining of Longwall 4 in 2009.
96Dr Cotter and Ms Hellwig's evidence did not positively establish to the contrary. At best, their evidence was that subsidence induced changes to the rock surface of the outcrop at GG1 could not be categorically ruled out. However, this evidence does not establish the positive fact that the physical signs of deterioration near the grinding grooves GG1 were caused by subsidence induced by Ashton's longwall mining or first workings. The onus of proving that Ashton, by its acts, has caused harm to the grinding grooves rests on Mr Lester. The evidence of Dr Cotter and Ms Hellwig does not permit Mr Lester to discharge this onus of proof.
97Accordingly, I find that Mr Lester has not established that Ashton has harmed the Aboriginal object that is the grinding grooves GG1 on the outcrop at the Waterhole site.
98I also find that Mr Lester has not established that Ashton has harmed any Aboriginal objects in erecting a new fence at the Waterhole site.
99First, there was no evidence that there was any Aboriginal object along the line of the new fence erected or that any Aboriginal object was harmed in the process of erection of the fence. Mr Lester's submission in closing address that the Court should assume that there are Aboriginal objects at that location because they had been recorded as occurring at other locations in the Waterhole site is rejected. Mr Lester bears the onus of proving that there were Aboriginal objects along the line of the new fence and that such objects were harmed by the erection of the new fence. Mr Lester has failed to discharge this onus.
100Secondly, Mr Lester's argument that Ashton has breached condition 7 of the Court-issued AHIP is misplaced. Even if condition 7 were to have been breached (and for the reasons I give below I do not so find), that does not cause Ashton to breach s 86(1) of the Parks Act. Non-compliance with conditions of an AHIP would only be relevant to rebut any defence that might be raised by Ashton under s 87(1) that any harm caused to Aboriginal objects was authorised by the AHIP. However, in this case, the only relevant AHIP, the Court-issued AHIP, does not authorise harm to any Aboriginal objects by construction of a fence 70m or more from the Waterhole site grinding grooves. Ashton, therefore, does not rely on the Court-issued AHIP as a defence to any breach of s 86(1) of the Parks Act. Hence, any non-compliance by Ashton with condition 7 of the Court-issued AHIP will not be relevant to and could not establish Mr Lester's claim that Ashton has breached s 86(1) of the Parks Act by erecting the new fence within 70m of the Waterhole site grinding grooves.
101Thirdly, in any event, I find that Mr Lester has not established that Ashton has contravened condition 7 of the Court-issued AHIP. Even if condition 7 is to be construed as prohibiting the erection of a fence within 70m of the Waterhole site grinding grooves (that is, that erection of a fence can be construction), the evidence does not establish that Ashton did erect a fence within 70m of the Waterhole site grinding grooves.
102Mr Wesley's evidence is that there was an original fence at the Waterhole site but some sections of that fence were less than 70m from the grinding grooves. After condition 7 of the Court-issued AHIP was imposed Ashton undertook additional fencing at those places where the original fence was less than 70m from the grinding grooves. The original fencing was not removed following the installation of the 70m fencing. Both fences have remained in place and the construction activities were kept outside the perimeter of the fences (para 26 of Mr Wesley's affidavit of 14 May 2012).
103Mr Wesley annexed a plan showing the locations of the original and additional fencing. Overlaid on the plan were the locations of each of the grinding groove sites GG1, GG3 and GG4, and an elliptical radius of 70m from these grinding groove sites. The location of the additional fencing is outside the 70m radius, establishing that the additional fencing is more than 70m from the grinding grooves.
104The evidence given by Mr Franks and Dr Cotter of having seen new fencing and fencing tools at the Waterhole site does not contradict Mr Wesley's evidence. It is not in issue that a new fence was erected. Mr Franks' and Dr Cotter's evidence does not establish that the new fence was within 70m of the grinding grooves at the Waterhole site.
105Mr Lester submitted that condition 7 required that the 70m radius be calculated from the outer boundary of the whole Waterhole site and not from the grinding grooves within the Waterhole site. On this construction of condition 7, some sections of the new fence might be within the 70m radius.
106I reject this submission. Condition 7 fixes the 70m radius by reference to 'the Waterhole Site grinding grooves', not 'the Waterhole site'. The inclusion of the reference to the grinding grooves must be taken to be deliberate and be a reference to the sets of grinding grooves known as GG1, GG3 and GG4 within the Waterhole site. Furthermore, Mr Lester's construction of condition 7 is impractical and unworkable. Condition 7 of the Court-issued AHIP required clear fencing of the site. A fence 70m away from the outer boundary of the whole Waterhole site would cross the New England Highway at two locations and have a section of the fence on the other side of the highway. Not only would such a fence not be able to be erected, it would not in any event secure the Waterhole site as entry to the site would be possible from the highway.
107For these reasons, I find that Mr Lester has not established that Ashton has harmed any Aboriginal objects by erecting the new fence at the Waterhole site, in breach of s 86(1) of the Parks Act.