Terramac, an Illinois, USA-based manufacturer of tracked carrier vehicles, reported that copper producer Asarco, a subsidiary of Grupo Mexico, is the first mining company to use a Terramac RT9 rubber track crawler carrier. According to Terramac, Asarco custom-ordered the vehicle—the only rubber track crawler carrier wholly made in North America—mounted with a 60-ft (18.2-m) Precision Industries spray boom. Designed to broadcast a continuous mist of magnesium chloride and water mixture, the crawler-mounted boom will be used to suppress dust resulting from high heat and wind at the tailings storage facilities at Asarco’s Mission Complex in Arizona.
The crawler-mounted spray boom offered Asarco an alternative to using wheeled vehicles or contracting spray planes for dust control near the tailings ponds. In addition, the RT9 has twice the payload capacity of the previous carrier Asarco had been using, at approximately the same cost as the smaller rig.
Terramac noted that the RT9’s footprint has the lowest psi of carriers in its class; at full payload capacity of 18,000 lb (8,160 kg), the RT9’s tracks exert only 4.9 psi or less on the surface—lower than that of a carrier half its size—reducing the chances of sinking or creating ruts near the tailings ponds.
The ability to equip the RT9 with a 1,600-gal (6,000-l) tank allows the mine to cut the frequency of refills and corresponding downtime by half. The spray is set to follow a specific flow rate, and is guided by a GPS unit in a precise coverage pattern. Terramac also claims the RT9’s 2-speed hydrostatic travel system with automatic downshift delivers 30% more power and torque to its tracks with 30% more hydraulic output than other carriers.
Travel motor covers and a reinforced belly pan protect vulnerable parts of the RT9’s operating system. A tilt-up hood, frame cleanouts, removable pivot shaft plates, easy-access maintenance points, and a fully enclosed exhaust and air cleaning system make the unit well-suited for use in the demanding environment of a large surface mine.
In total, Asarco’s three open-pit mines and the Hayden smelter in Arizona produce 300–350 million lb (663–774 kt) of anode copper annually. Asarco’s copper refinery in Texas refines the anodes to produce copper cathode, rod and associated by-products.
For more information on Terramac tailings dust control, visit http://www.terramac.com/gotdust/.