From 2000-04 Dr Murry Cave was a geological adviser on the Pike River mine to land owner the Department of Conservation as part of the resource consent and access process.
In 2007 he warned of geological risks associated with the Pike River mine.
Two issues in particular are extremely relevant in the light of the recent tragic events at the mine site.
Cave said there was an active fault that needed to be crossed underground, presenting 'a zone of considerable and sustained ground stresses'.
Secondly, he said there was a pit bottom with 'deep highly gassy coals 'and the associated risk of 'outburst' - gas pressure-forced explosive events at the coal face.
His comments have recently been backed by University of Canterbury engineering and mining geologist David Bell. He has said that the 'Hawera Fault zone' running through the mine shaft allowed pockets of methane gas to build up
In 2007 Pike River Coal (PRC) chairman John Dow, also a trained geologist, said that some of Cave's assumptions were wrong, notably that there was an active fault through the mine. He argued that the fault was not active and was in very old rock.
Dow said Pike River was a different proposition from some of other mines on the West Coast. Dow said the mine 'was shallower and without some of the other potential problems like outburst' that Cave had claimed were present.
A story being circulated at the time was that Cave was hostile to Pike River because he was annoyed that the project was given the go ahead by Chris Carter, the Minister for the Environment
Carter over-ruled the recommendations of DoC that the project be turned down.
In a letter to the Greymouth Evening Star in May 2007 Peter Whittall , who was at the time the General Manager of PRC, slammed Murry Cave. Wrote Whittall:
In yesterday’s Mail Box (22/5/07) Dr Murry Cave, under the guise of giving “advice” to potential investors in the Pike River Coal share float, made a number of inaccurate, inappropriate and ill informed statements. Dr Cave drew parallels between Pike River and a number of other mines operating in different areas, in different seams, at different depths and by different companies that bear little relevance to the Pike River mine development.
Pike River will extract coal from the Brunner Seam. The seam has approximately 6.5 kilometre of outcrop along the escarpment in the Paparoa ranges and the pit bottom will be at a depth of 80 to 100 metres with the majority of the mine is at a depth less than 200 metres. Dr Cave’s references to Mt Davy, operating in a very deep, low permeability, outburst prone seam and the tragic deaths at that mine are extremely inappropriate. Similarly Dr Cave’s vague references to the production life of Strongman 2, is as irrelevant as comparison to any other mine in NZ or overseas as the particular mining parameters and extent of mining area and resource are different.
Finally, Dr Cave’s description and assessment of conditions underground at Pike River, and in particular the pit bottom area, are inaccurate and ill informed. I am not aware of Dr Cave’s definition of an “active fault” or why it is applied here, and his description of deep, highly gassy coals and associated risk of outburst bears no relationship with the shallow, moderately gassy, non-outburst prone conditions at Pike River.
Pike River registered its prospectus on 22 May 2007 in both New Zealand and Australia. The prospectus sets out the benefits and risks associated with the mine development as well as reports from independent experts far better acquainted with the Pike River development than Dr Cave. Dr Cave is correct in one aspect however. That potential investors in any company need to consider all factors relevant to that investment decision.
So in 2007 Whittall claimed that Pike River was characterised by 'shallow, moderately gassy, non-outburst prone conditions.'
He also denied that Pike River had a pit bottom with deep highly gassy coals and such assessments were 'inaccurate and ill informed'.
In the light of the two devastating explosions at the mine in recent days, resulting in 29 men losing their lives, the question has to be asked whether the owners and management of Pike River Coal were wrong about the mine's geological characteristics.
One correspondent to this blog has suggested that an inaccurate assessment of 'environmental conditions' at Pike River means that the mine 'has been developed with much less evaluation drilling and fewer surface gas evacuation facilities than would normally be the case. I would guess that there are numerous gas-bearing fracture systems within the seam that are only found when mined into. These would be within small faults and fracture zones related to the Hawera Fault. In a properly developed mine these fractures and faults would be evaluated as fully as possible before mine development.'