Excavation contractors in Ravalli County, MT

Montana is the shale-and-rock end of the northern plains. The glaciated east (Great Falls, Havre, Glasgow) sits on glacial till and Tertiary sediments over the Pierre and Bearpaw shales, and the bentonitic shales bring the northern plains' worst ground: smectite clay that swells and shears, landslide-prone bluffs along the Missouri and Milk rivers, and shrink-swell behavior severe enough to shape every rural foundation. Saline seeps (discharge wet spots that kill crops) mark the shale uplands, and the state's alkaline soils complicate septic design. Digging in the till plains is easy where the shale is deep; shallow shale bedrock appears in the breaks. West of the Continental Divide the Northern Rockies take over: crystalline Belt Series rock, glacial valley fill, steep slopes (30-80 percent in the mountain counties), and the only serious blasting in the state. Frost runs 42-60 inches, the deepest in the lower 48. Hydric soils are rare in the arid east, common in the wet mountain valleys.