New Mexico Administrative Code › Title 20 - ENVIRONMENTAL PROTECTION › Chapter 6 - WATER QUALITY › Part 7 - GROUND WATER PROTECTION - SUPPLEMENTAL PERMITTING REQUIREMENTS FOR COPPER MINE FACILITIES › Section 20.6.7.21 - REQUIREMENTS FOR COPPER MINE WASTE ROCK STOCKPILES

Current through Register Vol. 35, No. 13, July 16, 2024
A.
Material characterization
				requirements.
(1)
Material
				characterization and acid mine drainage prediction.
All waste rock
				stored, deposited or disposed of at a copper mine facility shall be evaluated
				for its potential to generate acid and to release water contaminants at levels
				in excess of the standards of 20.6.2.3103 NMAC. A plan for determining the
				potential of the material to release water contaminants, and the method for
				such evaluations shall be submitted to the department for approval in a
				material characterization plan that includes the following.
(a) The geologic, mineralogical, physical,
				and geochemical characteristics of the material stored, deposited or disposed
				of at the copper mine facility.
(b)
				A sampling and analysis plan to provide representative samples of the entire
				range of material stored, deposited or disposed of at the copper mine facility.
				The plan shall include quality assurance/quality control procedures to be
				implemented to ensure the validity of the sample results. The plan shall
				consider the following factors in collecting and establishing representative
				samples.
(i) lithological
				variations;
(ii) particle size
				distribution of each lithology;
(iii) hydraulic conductivity, water content
				and matric suction relationship for each lithology;
(iv) mineralogical and textural
				variations;
(v) the nature and
				extent of sulfide mineralization;
(vi) color variation;
(vii) degree and nature of
				fracturing;
(viii) variations in
				oxidation and reducing conditions; and
(ix) the nature and extent of secondary
				mineralization.
(c) A
				static testing program using, at a minimum, acid/base accounting, or a
				department approved equivalent testing method, to evaluate the acid generation
				and neutralization potential of the material; and meteoric water mobility
				procedure or other department approved method for whole rock testing to
				determine water contaminant leaching potential.
(d) If the results of static testing indicate
				that a material may be acid generating or may generate a leachate containing
				water contaminants, a kinetic testing program shall be proposed to evaluate
				reaction rates, provide data to estimate drainage quality, the lag time to
				acidification of the material, and primary weathering and secondary mineral
				precipitation/dissolution as it may affect acidification, neutralization and
				drainage quality. The length of and means of determining when kinetic tests
				will be discontinued shall be approved by the department prior to
				implementation of the kinetic testing program.
(e) If the results of the static testing or
				kinetic testing indicate that the material will be acid generating or generate
				water contaminants, and the materials will be placed outside of an open pit
				surface drainage area, a plan shall be submitted to the department to evaluate
				whether discharges of leachate from the stockpile may cause an exceedance of
				applicable standards, including an evaluation of the geology and hydrology of
				the area where the material is to be placed. The plan may include either a
				department approved model or other department approved demonstration.
(f) If an interceptor system pursuant to
				Subparagraph (d) of Paragraph (1) of Subsection B of this section or a liner
				system is proposed for storage or disposal of waste rock, the kinetic testing
				program is not required.