In production with augers since 1985 and with three Terex highwall miners having been used for the last 34 months, Contour has produced 2.069 million short tons (1.877 million tonnes) of coal during the period – an average of well over 60,000t (56,900 tonnes) monthly.

“Our maximum monthly production came to 78,862t [71,560 tonnes] in March 2007, and that beat our previous monthly record by just over 600 tons,” Contour chief operating officer Dave Bundy said.

“When you consider that the seam was averaging 52 inches [1.47 metres] in height, it shows just how productive the machines can be, even when we are using a low-seam cutter module.”

The company, which serves as a contract miner in the Appalachian region and has worksites in both West Virginia and Kentucky, said one of the Terex miner units using a low-seam cutter module was able to mine in seam for 98 out of 132 entries at a depth of 1000 feet in a 30in (76cm) seam. The system, the complex noted, worked four days a week at an average monthly rate of 40,000t (36,287 tonnes).

“The Terex system is capable of producing coal in seams as low as 28 inches [0.76m] and to a penetration depth of 1000ft [300m], averaging 30-40t [27-36 tonnes] per man-hour with a standard three to four-man crew,” Terex pointed out while acknowledging Contour’s success.

Terex’s highwall mining system is available with a low or high-seam cutter module, making work in areas with two or more seams of varying thickness much more accessible. The low-seam cutters are designed to mine 30-64in (0.76-1.62m) thicknesses while high-seam modules are ideal for 50in to 10ft (1.27-3.05m) seam heights.

According to the OEM’s statistics, 70% of coal reserves at minesites can be extracted with its miner units at bench widths as narrow as 60ft (18m).

West Virginia-based Terex operates in four business segments, including aerial work platforms, construction, cranes, and materials processing and mining.