Dust Control – Soil Stabilization – Erosion Control

Posts Tagged ‘mining’

The design of the latest Cat mining trucks exceeds its predecessors and offers the ultimate in productivity, durability and low cost of operation even in the most challenging mining operations.

97F Cat® Mining Truck
The 797F, with 4,000-horsepower (2983 kW) and rated payload capacities to 363 tonnes, combines the strengths of its predecessors with a new engine, redesigned operator station and custom body systems to deliver even lower costs per tonne – with less environmental impact.

The 797F also offers easier maintenance and enhanced safety provisions. Ground level service points ease access, and 1,000-hour hydraulic filter service intervals reduce required maintenance. Safety enhancements include wider walkways, a rear access ladder and a bumper-mounted, three-way, lock-out tag-out box.

The 20-cylinder, 4,000-gross-horsepower Cat C175-20 ACERT engine has a single engine block and is the heart of the new truck. The engine has accumulated more than a quarter-million hours of field testing in mining trucks and power-generating systems. The C175 displaces 5.3 litres (323 in³) per cylinder – for a total displacement of 106 litres (6,458 in³). The 797F develops 450 horsepower more than its predecessor, the 797B, which used a 24-cylinder Cat 3524B engine displacing 117 litres (7,143 in³).

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A month ago, U.S. Rep. Gabrielle Giffords told a Green Valley newspaper that she’s not “anti-mining.” Late last week, she proved it. At a three-hour tour of Freeport McMoran’s Sierrita complex north of Green Valley, at a site where copper has been mined for a century, Giffords was as effusively friendly as she has been critical of the proposed Rosemont Mine in the Santa Rita Mountains across the valley.

She had many reasons, but they boiled down to differences between living with an existing mine in a long-compromised area and bringing a new one into a more pristine site — and to differences in trust between neighbors of Freeport and of Rosemont.

Freeport’s mine — where mining has occurred for a century — employs 1,000 people and sprawls 1.5 by 2 miles in its open pit. A peek inside the 1,500 foot deep pit shows about 25 mine benches, each about 50 feet tall, heading toward the bottom. To the pit’s west lies the rocky Sierrita Mountains.

The mine processes 160,000 to 170,000 tons of ore daily, down in this recessionary area from 220,000 a year ago. Rock is blasted five days a week, three to five times daily. Electric shovels cost $25 million and stand 64 feet high. Each of 18 haul trucks can carry 162 tons for crushing. A mill building stands five stories tall.

Finally, the company’s 3,500 acre tailings impoundment stands as a testimony to past dust complaints from residents but also offers promise for future groundwater cleanups and newer dust control equipment, since the company is proposing to do a massive, very expensive cleanup of tainted groundwater lying underneath and spreading from the tailings.

At one point, Giffords marveled to company officials: “You’ve got quite a piece of land. How did it get like this?”

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