The molten steel went beyond its required specifications and had to be recycled which resulted in the stopping of a casting machine. The impact was a cost to the business of in excess of $100,000, according to Mr Tarrant. (Ex 18 - para 34)
70 The termination letter refers to a potential to cause a steel breakout with risk of serious injury. This claim also takes in for consideration the temperature of the heat in question.
71 A breakout refers to the furnace being breached and the molten steel (some 250 tonnes or plus) pouring out. There was no evidence of such an event ever happening. However, the termination letter referred to the "potential" of a steel breakout with risk of serious injuries to operations personnel.
72 There are factors contributing to the potential of a breakout: The Applicant, under cross-examination, referred to the lining of the furnace and the condition of that lining; he also referred to the campaign life of the furnace (that is, the number of heats the furnace can withstand.) (Tr 12/07/06 - p 15, line 3 to p 20, line 15)
73 Mr Staff gave evidence, under cross-examination, that temperature is a factor, as well. He was asked to state, at what temperature, a furnace would fail. He said that temperatures above 1720°C would bring about "a very high risk of having a break out." He could not give a specific temperature at which the furnace would break out. As well, he said the refractory bricks (which line the inside of the furnace and act as an absorber) do not come with a guarantee that they are safe to 1720°C. (Tr 13/07/06 - p 65, line 3 to p 66, line 8)
74 Before considering the temperature reading for the heat in question, the Commission will put that consideration into context by referring to evidence given about heat temperatures. Thus, Mr Staff deposed that at the beginning of the heat process, the hot metal is about 1350°C. The average end point temperature (at completion of the heat) is 1650°C and the temperature typically ranges from 1320° to 1710°C. End point temperatures greater than 1680°C are only required for a small number of special grades of steel. At the completion of the heat, the initial hot metal has been converted into liquid steel. (Ex 19 - paras 16 to 19)
75 For the heat in question, the temperature was aimed to be at 1662°C. (Van Der Weyden - Ex 22 - para 74)