Drill surpasses million metre mark

A DIESEL-hydraulic P&H 250XP hard rock production drill on September 25 surpassed 1 million metres of cumulative blast hole depth in service to a remote diamond mine operated by Argyle Diamonds Limited (ADL). Located in the rugged East Kimberley region of Western Australia and owned and operated by Rio Tinto Limited, the ADL mine is the world’s largest supplier of diamonds, producing approximately 30 million carats each year or about one quarter of total natural diamond production.

Argyle is the world’s primary source of rare pink diamonds that have become ADL’s signature product.

Placed into service in December 1999 by P&H MinePro Services – Australasia, the P&H 250XP quickly encountered ultra-hard rock formations in the mine, including Henzman quartz strata.

The hardness of that type of quartz ranges from 26,000 psi / 180 megapascals up to 60,000 psi / 410 megapascals (the force required to fracture the Henzman quartz during the drilling process) and approaches the hardness of iron ore which is among the most challenging of rock formations encountered in the mining industry. To counter and compensate for the difficult drilling conditions, P&H Mining Equipment, which designed and built the 250XP, and MinePro, which provides service support for the drilling rig, worked together with mine management to optimize the machine’s productivity and reliability performance.

Structural reinforcement of the drill mast and carriage and new vibration-dampening hoses and plumbing changes were among the primary upgrades applied to enhance drill performance in the production of explosives-containing blast holes required to help ADL sustain a primary crusher throughput rate of approximately 1,800 tonnes of ore per hour, 24 hours a day throughout the year.

Beyond the factory-supplied upgrades, MinePro worked with mine management to develop a drill service support logistics and preventive maintenance program aimed at sustaining relatively high availability levels of around 90 percent in the difficult and remote mining environment.

The P&H 250XP has racked up over 38,000 production hours since 2000, helping to liberate about 300,000 tonnes of rock with each production blast.

P&H 250XP drills also play a key role in the diamond mining industry in Southern Africa where several of the rigs are applied to the mining of kimberlite diamond pipes formed by the violent, supersonic eruption of deep-origin volcanic events several million years ago.

ADL is unlike the diamond mines in Southern Africa, however, in that its diamonds are contained within lamproite ore, the basement of which in Western Australia is more than 2.5 billion years old.

Since ADL commenced production in 1983, the mine has produced over 670 million carats of diamonds, about 90 percent of which are destined for the jewellery industry.

ADL operations are both surface and underground, they employ about 800 people including local Aboriginals, and they generate millions of dollars in annual exports from Western Australia.

P&H Mining Equipment

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