(1) Each operator who conducts strip or underground mining operations on prime farmland shall, within the area identified as prime farmland before disturbance:
(a) if the approved postmining land use is not cropland:
(i) randomly establish test plots that will be cropped until restoration of the premining productivity has met the requirements of this rule. The remainder of the area not used for test plots must be revegetated consistent with the standards of ARM 17.24.711, 17.24.713, 17.24.714, 17.24.716 through 17.24.718, 17.24.721, 17.24.723 through 17.24.726, and 17.24.731 and with the approved postmining land use. When restoration of the premining productivity has been demonstrated, the operator shall revegetate the test plots consistent with the standards of ARM 17.24.711, 17.24.713, 17.24.714, 17.24.716 through 17.24.718, 17.24.721, 17.24.723 through 17.24.726 and 17.24.731 and with the approved postmining land use; or
(ii) crop the entire area of disturbed prime farmland until restoration of the premining productivity is demonstrated. The operator shall then revegetate the entire area consistent with ARM 17.24.711, 17.24.713, 17.24.714, 17.24.716 through 17.24.718, 17.24.721, 17.24.723 through 17.24.726, and 17.24.731 and with the approved postmining land use; or
(b) if the approved postmining land use is cropland, permanently reclaim the area to cropland.
(2) All prime farmlands reclaimed either temporarily or permanently as cropland must meet the following revegetation requirements:
(a) following soil replacement, the operator shall implement the revegetation and erosion-control plan approved by the department under ARM 17.24.324, as follows:
(i) This plan must be carried out in a manner that encourages prompt vegetative cover and recovery of productive capacity.
(ii) Nutrients, other soil amendments, and other management techniques such as irrigation must be applied as approved by the department and as necessary to be consistent with (d) .
(iii) The provisions of ARM 17.24.713 and 17.24.714 must be met.
(b) Within a time period specified in the permit, but not to exceed 10 years after completion of backfilling and rough grading, areas to be reclaimed either temporarily or permanently to cropland must be planted to the crops that have been approved under ARM 17.24.324 and that are commonly grown on surrounding prime farmland. As appropriate, the crops may be grown in rotation with hay or pasture crops as defined for cropland in ARM 17.24.825(1) . The department may approve a crop use of perennial plants for hay where this is a common long term use of prime farmland soils in the surrounding area;
(c) if row crops are the dominant crops grown on prime farmland in the area, the row crop requiring the greatest rooting depth must be one of the reference crops;
(d) the level of management must be equivalent to that occurring on the reference area(s) or on which the target yields are based pursuant to (e) ; and
(e) (i) revegetation success on prime farmlands must be determined upon the basis of a comparison of actual crop production on the disturbed area and the crop production on reference areas meeting the following requirements:
(A) reference areas must consist of representative undisturbed prime farmland supporting the crops commonly grown on those prime farmlands proposed for disturbance;
(B) reference areas must have soils, slopes, and other pertinent characteristics comparable to those proposed for disturbance; and
(C) the location of reference areas and the yields from them that are used to determine revegetation success pursuant to (2) (e) (i) must be determined with the concurrence of the Montana state office of the U.S. natural resources conservation service.
(ii) if undisturbed prime farmland is not available for comparison purposes, comparison of production on the disturbed area must be made with target yields approved by the department and meeting the following standards:
(A) target yields for a given year must be determined on the basis of current yield records of representative local farms, with the concurrence of the Montana state office of the U.S. natural resources conservation service, or by the average county yields recognized by the U.S. department of agriculture;
(B) these yields must be adjusted as necessary by the Montana state office of the U.S. natural resources conservation service for local yield variation that is associated with differences between undisturbed prime farmland soil and all other soils that produce the crops of interest within the locale or the county;
(iii) under either procedure in (2) (e) (i) or (ii) , crop production of the reference area or the target yield must be adjusted, as necessary, with the concurrence of the Montana state office of the U.S. natural resources conservation service, for:
(A) disease-, pest-, and weather-induced seasonal variations; or
(B) differences in specific management practices where the overall management practices of the crops being compared are equivalent;
(f) crop production on disturbed prime farmland must be determined based upon a minimum of three consecutive crop years of data;
(i) for permanent cropland, these three years of data must include the last year of a minimum 10-year period of responsibility preceding the application for phase III bond release;
(ii) for temporary test plots, these three years of data must include the last year of a minimum 10-year period of crop production;
(g) crop production on the prime farmland reference area must be determined based upon a minimum of three consecutive crop years of data consistent with (f) (i) or (ii) above, as appropriate; and
(h) revegetation on prime farmland is considered successful when the crop yield for each of the three years is equivalent to, or higher than, that on the reference area or the target yield. This equivalence must be shown at least at the 10% level of significance using statistically appropriate sampling techniques approved by the department in consultation with the Montana state office of the U.S. natural resources conservation service.