regulatory authority after consider- mining operator to re-establish baseation of soil, climate, and other char- line pollutant levels in accordance acteristics of a region or State. This with the statistical procedures conterm does not apply to those situations tained in Appendix B of this part, prein which an operator is mining on flat existing discharge limitations at existor gently rolling terrain, on which an ing remining operations shall remain occasional steep slope is encountered subject to baseline pollutant levels esand through which the mining oper- tablished during the original permit ation is to proceed, leaving a plain or application. predominantly flat area. (d) The effluent limitations in this (e) The term new source remining oper subpart apply to pre-existing disation means a remining operation at a charges until the appropriate SMCRA coal mine where mining first com authority has authorized bond release. mences after February 22, 2002 and subsequently becomes an abandoned mine. $ 434.72 Effluent limitations attainable § 434.71 Applicability. by the application of the best prac. ticable control technology currently (a) This subpart applies to pre-exist- available (BPT). ing discharges that are located within (a) The operator must submit a siteor are hydrologically connected to pol specific Pollution Abatement Plan to lution abatement areas of a coal re the permitting authority for the pollumining operation. (b) A pre-existing discharge that is tion abatement area. The plan must be intercepted by active mining or that is approved by the permitting authority commingled with waste streams from and incorporated into the permit as an effluent active mining areas for treatment is limitation. The Pollution subject to the provisions of $ 434.61 Abatement Plan must identify characCommingling of waste streams. For the teristics of the pollution abatement purposes of this subpart, $ 434.61 re area and the pre-existing discharges. quires compliance with applicable The Pollution Abatement Plan must be BPT, BAT, BCT, and NSPS effluent designed to reduce the pollution load limitations in subparts C, D, and F of from pre-existing discharges and must this part. Section 434.61 applies to the identify the selected best management commingled waste stream only during practices (BMPs) to be used. The plan the time when the pre-existing dis must describe the design specificacharge is intercepted by active mining tions, construction specifications, or is commingled with active mine maintenance schedules, criteria for wastewater for treatment or discharge. monitoring and inspection, and exAfter commingling has ceased, the pre- pected performance of the BMPs. The existing discharge is subject to the pro BMPs must be implemented as specivisions of this part. fied in the plan. (c) In situations where coal remining (b) (1) Except as provided in 40 CFR operations seek reissuance of an exist- 125.30 through 125.32 and paragraph ing remining permit with BPJ limita- (b)(2) of this section, the following eftions and the regulatory authority de- fluent limits apply to pre-existing distermines that it is not feasible for a re- charges: EFFLUENT LIMITATIONS Pollutant Requirement (i) Iron, total (ii) Manganese, total May not exceed baseline loadings (as defined by Appendix B of this part). May not exceed baseline loadings (as defined by Appendix B of this part). May not exceed baseline loadings (as defined by Appendix B of this part). (iii) Acidity, net (iv) TSS During remining and reclamation, may not exceed baseline loadings (as defined by Appendix B of this part). Prior to bond release, the pre-existing discharge must meet the applicable standards for TSS or SS contained in Subpart E. A pre-existing discharge is exempt from meeting standards in Subpart E of this part for TSS and SS when the permitting authority determines that Subpart E standards are inteasible or impractical based on the site-specific conditions of soil, climate, topography, steep slopes, or other baseline conditions provided that the operator demonstrates that significant reductions of TSS and ss will be achieved through the incorporation of sediment control BMPs into the Pollution Abatement Plan as required by paragraph (a) of this section. (2) If the permitting authority determines that it is infeasible to collect samples for establishing the baseline pollutant levels pursuant to paragraph (b)(1) of this section, and that remining will result in significant improvement that would not otherwise occur, then the numeric effluent limitations in paragraph (b)(1) of this section do not apply. Pre-existing discharges for which it is infeasible to collect samples for determination of baseline pollutant levels include, but are not limited to, discharges that exist diffuse groundwater flow that cannot be assessed via sample collection; a base flow to a receiving stream that cannot be monitored separate from the receiving stream; a discharge on a steep or hazardous slope that is inaccessible for sample collection; or, a number of preexisting discharges so extensive that monitoring of individual discharges is infeasible. 8 434.75 New performance standards (NSPS). Except as provided in $ 434.72(b)(2), a pre-existing discharge from source remining operation must comply with the effluent limitations listed in § 434.72(b) for iron, manganese, acidity and total suspended solids. The operator must also submit and implement a Pollution Abatement Plan as required in $ 434.72(a). as a Subpart H-Western Alkaline Coal Mining SOURCE: 67 FR 3407, Jan. 23, 2002, unless otherwise noted. $ 434.73 Effluent limitations attainable by application of the best available technology economically achievable (BAT). Except as provided in 40 CFR 125.30 through 125.32 and 434.72(b)(2), a pre-existing discharge must comply with the effluent limitations listed in $ 434.72(b) for net acidity, iron and manganese. The operator must also submit and implement a Pollution Abatement Plan as required in § 434.72(a). means 8 434.80 Specialized definitions. (a) The term brushing and grubbing area means the area where woody plant materials that would interfere with soil salvage operations have been removed or incorporated into the soil that is being salvaged. (b) The term regraded area means the surface area of a coal mine that has been returned to required contour. (c) The term sediment undissolved organic and inorganic material transported or deposited by water. (d) The term sediment yield means the sum of the soil losses from a surface minus deposition in macro-topographic depressions, at the toe of the hillslope, along field boundaries, or in terraces and channels sculpted into the hillslope. (e) The term topsoil stockpiling area means the area outside the mined-out where topsoil is temporarily $ 434.74 Effluent limitations attainable by application of the best conventional pollutant control technology (BCT). Except as provided in 40 CFR 125.30 through 125.32 and 434.72(b)(2), a pre-existing discharge must comply with the effluent limitations listed in § 434.72(b) for total suspended solids. The operator area stored for use in reclamation, including containment berms. (f) The term western coal mining operation means a surface or underground coal mining operation located in the interior western United States, west of the 100th meridian west longitude, in an arid or semiarid environment with an average annual precipitation of 26.0 inches or less. $ 434.81 Applicability. (a) This subpart applies to alkaline mine drainage at western coal mining operations from reclamation areas, brushing and grubbing areas, topsoil stockpiling areas, and regraded areas. (b) This subpart applies to drainage at western coal mining operations from reclamation areas, brushing and grubbing areas, topsoil stockpiling areas, and regraded areas where the discharge, before any treatment, meets all the following requirements: (1) pH is equal to or greater than 6.0; (2) Dissolved iron concentration is less than 10 mg/L; and (3) Net alkalinity is greater than zero. (c) The effluent limitations in this subpart apply until the appropriate SMCRA authority has authorized bond release. undisturbed conditions. The Sediment Control Plan must be approved by the permitting authority and be incorporated into the permit as an effluent limitation. The Sediment Control Plan must identify best management practices (BMPs) and also must describe design specifications, construction specifications, maintenance schedules, criteria for inspection, as well as expected performance and longevity of the best management practices. (b) Using watershed models, the operator must demonstrate that implementation of the Sediment Control Plan will result in average annual sediment yields that will not be greater than the sediment yield levels from pre-mined. undisturbed conditions. The operator must use the same watershed model that was, or will be, used to acquire the SMCRA permit. (c) The operator must design, implement, and maintain BMPs in the manner specified in the Sediment Control Plan. $ 434.83 Effluent limitations attainable by application of the best available technology economically achievable (BAT). Except as provided in 40 CFR 125.30 through 125.32, any existing western coal mining operation with drainage subject to this subpart must meet the effluent limitations in § 434.82. $ 434.84 Effluent limitations attainable by application of the best conven. tional pollutant control technology (BCT). (Reserved] § 434.82 Effluent limitations attainable by the application of the best practicable control technology currently available (BPT). Except as provided in 40 CFR 125.30 through 125.32, the following effluent limitations apply to mine drainage from applicable areas of western coal mining operations: (a) The operator must submit a sitespecific Sediment Control Plan to the permitting authority that is designed to prevent an increase in the average annual sediment yield from pre-mined, $ 434.85 New source performance standards (NSPS). Any new source western coal mining operation with drainage subject to this subpart must meet the effluent limitations in $ 434.82. FERRUGINOUS MINE DRAINAGE 1. Discharges from preparation plant TSS, pH, Iron Manganese SS, PH SS, PH APPENDIX B TO PART 434_BASELINE DE TERMINATION AND COMPLIANCE MON- tween the quartiles M , and M,; these values should be calculated using actual loadings (based on measured concentrations) when they are used to calculate R. This should be done in order to account for the full range of variability in the data. II. PROCEDURE FOR CALCULATING AND APPLY ING A SINGLE-OBSERVATION (MONTHLY) TRIGGER Two alternative methods are provided for calculating a single-observation trigger. One method must be selected and applied by the permitting authority for any given remining permit. I. GENERAL PROCEDURE REQUIREMENTS a. This appendix presents the procedures to be used for establishing effluent limitations for pre-existing discharges at coal remining operations, in accordance with the requirements set forth in Subpart G; Coal Remining. The requirements specify that pollutant loadings of total iron, total manganese, total suspended solids, and net acidity in pre-existing discharges shall not exceed baseline pollutant loadings. The procedures described in this appendix shall be used for determining site-specific, baseline pollutant loadings, and for determining whether discharge loadings during coal remining operations have exceeded the baseline loading. Both a monthly (single-observation) procedure and an annual procedure shall be applied, as described below. b. In order to sufficiently characterize pollutant loadings during baseline determination and during each annual monitoring period, it is required that at least one sample result be obtained per month for a period of 12 months. c. Calculations described in this appendix must be applied to pollutant loadings. Each loading value is calculated as the product of a flow measurement and pollutant concentration taken on the same date at the same discharge sampling point, using standard units of flow and concentration (to be determined by the permitting authority). For example, flow may be measured in cubic feet per second, concentration in milligrams per liter, and the pollutant loading could be calculated in pounds per year. d. Accommodating Data Below the Maximum Daily Limit at subpart C of this part. In the event that a pollutant concentration in the data used to determine baseline is lower than the daily maximum limitation established in subpart C of this part for active mine wastewater, the statistical procedures should not establish a baseline more stringent than the BPT and BAT effluent standards established in subpart of this part. Therefore, if the total iron concentration in a baseline sample is below 7.0 mg/L, or the total manganese concentration is below 4.0 mg/L, the baseline sample concentration may be replaced with 7.0 mg/L and 4.0 mg/L, respectively, for the purposes of some of the statistical calculations in this Appendix B. The substituted values should be used for all methods in this Appendix B with the exception of the calculation of the interquartile range (R) in Method 1 for the annual trigger (Step 3), and in Method 2 for the single observation trigger (Step 3). The interquartile range (R) is the difference be A. Method 1 for Calculating a Single Observation Trigger (L) (1) Count the number of baseline observations taken for the pollutant of interest. Label this number n. In order to sufficiently characterize pollutant loadings during baseline determination and during each annual monitoring period, it is required that at least one sample result be obtained per month for a period of 12 months. (2) Order all baseline loading observations from lowest to highest. Let the lowest number (minimum) be X1), the next lowest be X2), and so forth until the highest number (maximum) is X(n). (3) If fewer than 17 baseline observations were obtained, then the single observation trigger (L) will equal the maximum of the baseline observations (X(n)). (4) If at least 17 baseline observations were obtained, calculate the median (M) of all baseline observations: Instructions for calculation of a median of n observations: If n is odd, then M equals Xx1/2 + 1/2). For example, if there are 17 observations, then M = X(172+1/2) = X(9), the 9th highest observation. If n is even, then M equals 0.5 * (Xin/2) + X(n/2 + 1)). For example, if there are 18 observations, then M equals 0.5 multiplied by the sum of the 9th and 10th highest observations. (a) Next, calculate M, as the median of the subset of observations that range from the calculated M to the maximum xxn); that is, calculate the median of all x larger than or equal to M. (b) Next, calculate M2 as the median of the subset of observations that range from the calculated M, to Xin) ; that is, calculate the median of all x larger than or equal to M. (c) Next, calculate M3 as the median of the subset of observations that range from the calculated M2 to Xin) ; that is, calculate the median of all x larger than or equal to M2. (d) Finally, calculate the single observation trigger (L) as the median of the subset of observations that range from the calculated M, to X(n). |
