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removal using rubber-tired and tracked equipment . Guard rails <br /> and specially constructed berms have been installed in accordance <br /> with MSHA requirements . The Mine Safety and Health Administration <br /> (MSHA) has granted Mid-Continent a variance from constructing <br /> outside berms on mine haul roads . The variance was granted to <br /> alleviate problems associated with snow removal . The outside <br /> berms would impede outslope plowing and would also require Mid- <br /> Continent to push outside berm material downslope. Therefore the <br /> variance granted by MSHA improves road conditions while the <br /> practice reduces environmental impacts by reducing outslope road <br /> grading spoilage. <br /> Mine haulage by the all-wheel drive vehicles <br /> is also improved by requiring loaded trucks to travel on the <br /> inside cut and the unloaded trucks travel on the uphill grade <br /> outside fill material . <br /> Avalanche control has been a part of Mid- <br /> Continent ' s operations plan since the mine started in 1956 . Hand <br /> explosive charges were used initially or skiers above the snow <br /> chutes displaced the snow to create avalanches . The present <br /> method involves the use of a cannon fired projectile propelled by <br /> nitrogen gas . The 200 lb . portable cannon is mounted in a pickup <br /> truck or on 'a small trailer. The avalauncher has the capability <br /> of hitting a target 100 feet in diameter, at ranges up to 2, 000 <br /> i <br /> yards . The plastic projectile is fin and roll-stabilized . The <br /> F <br /> standard payload is 1 . 5 lbs . of explosive having a detonation <br /> f <br /> rate of 25, 000 FPS . <br /> 41 <br />