17.24.320    PLANS FOR DISPOSAL OF EXCESS SPOIL

(1) Each application must contain descriptions, including appropriate maps and cross-section drawings, of the proposed disposal site and design of the spoil disposal structures according to ARM 17.24.520.   These plans must describe the geotechnical investigation, design, construction, operation, maintenance, and removal (if appropriate) of the site and structures in accordance with state and federal statutes and rules (see also 30 CFR 816.71 and 816.73).

(2) Each application must contain the results of a geotechnical investigation of the proposed disposal site, including the following:

(a) the character of bedrock and any adverse geologic conditions in the disposal area;

(b) a survey identifying all springs, seepage and ground water flow observed or anticipated during wet periods in the area of the disposal site;

(c) a survey of the potential effects of subsidence of the subsurface strata due to past and future mining operations;

(d) a technical description of the rock materials to be utilized in the construction of those disposal structures containing rock chimney cores and underlain by a rock drainage blanket; and

(e) a stability analysis including, but not limited to, strength parameters, pore pressures and long-term seepage conditions. These data must be accompanied by a description of all engineering design assumptions and calculations and the alternatives considered in selecting the specific design specifications and methods.

(3) If rock-toe buttresses or key-way cuts are required, the application must include the following:

(a) the number, location, and depth of borings or test pits determined with respect to the size of the spoil disposal structure and subsurface conditions; and

(b) engineering specifications utilized to design the rock-toe buttress or key-way cuts, which must be determined in accordance with (2)(e).

 

History: 82-4-205, MCA; IMP, 82-4-222, MCA; NEW, 1980 MAR p. 725, Eff. 4/1/80; AMD, 1989 MAR p. 30, Eff. 1/13/89; TRANS, from DSL, 1996 MAR p. 3042; AMD, 2024 MAR p. 255, Eff. 2/10/24.