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Mine 2004 SPCC 4.8 ELECTRICAL GEAR • There are 8 active transformer units in various locations throughout the minesite. These units are identified in Table 2, page 4 of 4. 4.8.1 Oil Inventory The total volume of transformer oil in the 8 active transformers onsite amounts to slightly more than 6,000 gallons. See Table 2, page 4 of 4. 4.8.2 Containment and Diversionary Structures In the Preamble to 40 CFR Part 112 as given in the Federal Register, July 17, 2002, pages 47054-5, it states: "Facilities that use oil operationally include electrical substations, facilities containing electrical transformers, and certain hydraulic or manufacturing equipment. The requirements for bulk storage containers may not always apply to these facilities. Facilities with equipment containing oil for ancillary purposes are not required to provide the secondary containment required for bulk storage facilities (§112.8(c))." Based on the preceding regulatory discussion, seconday containment is not required for electrical transformers. In the unlikely event that a transformer should completely rupture the oil inside would report to • the ground surrounding the unit. Stormwater runoff from Trapper Mine's permitted areas is contained with stormwater basins and sediment ponds that are designated CDPS discharge points under the NPDES program. The most likely amount spilled is expected to be less than l0 gallons. Any oil would likely be contained within the soil adjacent to the transformers. In the unlikely event oil would flow outside the immediate area of the transformers, it would likely be captured within one of the sediment ponds or CDPS basins. 4.8.3 Conformance with Applicable Requirements The overall housekeeping effort around transformers was observed to be good during site inspections. Applicable state guidelines are assumed to be the same as the Federal Regulations at 40 CFR Part 112, and therefore, under §112.7(j) the electrical transformer facilities discussed in this section are in conformance with applicable requirements. 4.9 OPERATING EQUIPMENT (MOBILE EQUIPMENT) Operating equipment or mobile equipment, for inclusion in this SPCC Plan, will refer to those vehicles that have oil in individual tanks with capacities of SS .gallons or greater. This determination is based on page 47044 of the July 17, 2002 Federal Register "Summary of Major Revisions to the Current SPCC Rules" table which states that the threshold (1320 gallons in • containers greater than 55 gallons) applies to storage capacity contained in operating equipment 13