Quarries closed over fertiliser asbestos scare Serpentine mining halted by WorkSafe over asbestos fears

Wednesday, 11 October 2017

A Ravensdown topdressing plane delivering fertiliser.

Asbestos safety fears have prompted WorkSafe to order three quarries to stop mining serpentine rock, and fertiliser company Ravensdown has suspended all movement of the material.

Serpentine rock containing natural asbestos is also sold by the other main rural services companies as an ingredient in farm fertiliser as a way to get magnesium into the soil.

Ravensdown chief executive Greg Campbell at the recent annual meeting.

It is estimated about 80 of farms, and predominantly those in Southland and central North Island, have used it at some stage.

One of the WorkSafe abatement notices was to Southland Serpentine at Mossburn owned and operated by partners Duncan and Lockey McGregor, and Bob and Lyn Pearson who declined to comment.

Serpentine rock is dug from the Mossburn quarry by a digger and transported to McGregors Concrete Te Anau for crushing into 3 millimetre particles before being distributed to fertiliser suppliers.

Another quarry company, Rorisons RMD, has operated lime and serpentine quarries in south Waikato for 50 years.

WorkSafe's deputy general manager assessments operations and support, Jo Pugh, said Ravensdown revealed that regular testing had shown the presence of low levels of asbestos in serpentine rock it was crushing.

WorkSafe requested test results from the quarries mining serpentine rock and Ravensdown manufacturing plants.

The tests showed asbestos at or below trace levels.

To ensure workers and others handling the product were protected, WorkSafe has placed prohibition notices on three operational quarries associated with the Ravensdown results.

It requires them to either produce test results showing no asbestos, or an asbestos management plan before they can re-start mining serpentine rock.

'We have received draft plans from two quarries and one is in the process of being prepared.

'A fourth quarry has returned test results indicating no presence of asbestos. A fifth quarry which has produced serpentine rock no longer operates.

'A prohibition notice has also been placed on a transport company which is currently storing the crushed product and an asbestos management plan is being prepared by the company.

'Once the plans are in place, or testing shows no presence of asbestos, WorkSafe will lift the prohibition notices and we expect that to occur in the next few days.

'Our risk assessment shows any risk to workers and others handling the product is very low to insignificant,' Pugh said.

The presence of asbestos in serpentine rock depends on the geology of the particular seam being mined, she said.

A Ravensdown spokesman said the company sourced serpentine rock from three quarries but declined to name them for commercial confidentiality reasons.

He said serpentine made up about 1 per cent of Ravensdown's $627 million annual sales.

'As part of Ravensdown's focus on health and safety, the co-operative took the precautionary measure of suspending sales of its Serpentine Super product on October 3.

'As a result of testing of our stocks and products in September, there had been a potential identification of a trace level of naturally occurring asbestos in some of our dunite serpentine rock supplies and manufactured Serpentine Super.

'It was a potential identification because since that date testing been negative.

'The product remains unavailable at this time pending further tests being conducted by a different laboratory.

'These measures are a precautionary approach because the original detected presence was at extremely low level.

'We are working on alternatives for customers. The suspended product is a relatively minor product in our portfolio. We do not use these dunite serpentine rocks for the manufacture of any other products so all other products are unaffected.

White asbestos or chrysotile can occur naturally in certain seams of the serpentine dunite family of rocks. The risk profile and concentrations of this naturally-occurring type are very different to those found in asbestos-containing building materials,' Ravensdown said.