The Mt Keith ultramafic intrusive extends for about 200 kilometres from
Agnew in the south to Wiluna in the north. It forms the host for a number
of nickel sulphide orebodies including Mt Keith and Honeymoon Well.
Long fibre minerals are associated with the orebodies. The presence of
these minerals impacts on the issue of tailings disposal from several
standpoints, particularly the slurry beaching properties and dust
generation from dry beaches. Central thickened discharge (CTD) is an innovative method of tailings
disposal that involves stacking tailings in a low conical hill instead of
storing them in cells. In appropriate circumstances this leads to savings in
capital costs and operating expenditure. The method was introduced to
Australia in 1981, and is currently employed at four operating mines,
Elura and Peak Gold, both at Cobar in NSW, McArthur River in the
Northern Territory, and Union Reefs near Pine Creek, also in the Northern
Territory. It is the proposed method for Century Zinc and Ernest Henry,
both in Queensland. The paper describes laboratory test work and design parameters for the
application of the method to tailings disposal at Honeymoon Well and
compares them with comparable data for other CTD systems. Of
particular relevance for design purposes are beach slope, density, and
water recovery. Wind tunnel tests were conducted on the Honeymoon
Well tailings samples to investigate dust generation from the dry beach
surface and it was concluded that dust generation from an undisturbed
beach would not occur because of crusting.