(1) In addition to the requirements imposed by ARM 17.24.203, 17.24.206, and 17.24.218 through 17.24.222, the department may require the following information as part of the plan of operation for a bentonite mining operation:

(a) an analysis of the soil and each major stratum in the overburden that includes determinations of:

(i) saturation percentage;

(ii) pH;

(iii) electrical conductivity;

(iv) sodium adsorption ratio;

(v) texture; and

(vi) additional characteristics the department may require.

(2) A soil analysis required under (1)(a) must describe:

(a) the identifying number and depth of each sample taken;

(b) the methods by which the samples were taken;

(c) the names and addresses of the persons who took the samples;

(d) the analytical methods used; and

(e) the names and addresses of the persons who analyzed the samples.

(3) A soil analysis required by (1)(a) must be accompanied by a map that describes:

(a) the soil types identified;

(b) the location and depth of each sample taken;

(c) thicknesses of soil and overburden to be stripped for each soil type; and

(d) the dominant vegetative species present on each soil type. 

(4) The department may also require that the plan of operation contain a description of the location and method of disposal of bentonite cleanings, stray bentonite seams, and overburden that are unsuitable for plant growth. Such materials must be buried under at least three feet of material suitable for sustaining the postmining vegetation, but if suitable burial material is not available, then the material that is unsuitable for plant growth must be laid and graded to a condition that is as good or better than the pre-mine condition, minimizes adverse impacts to plant growth, and blends into the surrounding area.

History: 82-4-422, MCA; IMP, 82-4-432, 82-4-434, MCA; NEW, 1994 MAR p. 1871, Eff. 7/8/94; TRANS, from DSL, 1996 MAR p. 2852; AMD, 2004 MAR p. 317, Eff. 2/13/04; AMD, 2016 MAR p. 513, Eff. 3/19/16.