2020-12-14_PERMIT FILE - C1981019A (2)

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RULE 2 PERMITS The hole selection for collection of the overburden and interburden rock for physio -chemical analysis used the Division's Guidelines for the Collection of Baseline Water Quality and Overhurden Geochemistry as a basis for selecting the sampling hole and location. The purpose of the physio -chemical analyses is to determine the chemical composition and assess the acid-forming, toxic -forming, or alkalinity -producing potential of overburden and interburden material within the Collom permit expansion area. The Division's Guidelines recommend sampling one hole per square mile, with a minimum of three per permit area. The drill holes that were selected are distributed sufficiently to meet this criterion for the Collom Pit. The holes selected to be overburden/interburden core holes were: C-04-04, C-04-14, C-04-25, C-04-36, C-05-26, and C-05-32. These drill holes are near or within the footprint of the Collom Pit. The locations of the core holes are shown on Map I IB and the data is summaried in Exhibit 6, Item 9. Logs of drill holes and test borings within the Collom project area can be found in Exhibit 6, Item 10 (Geologic Data for Collom Cross Sections — Drill Hole Information). Each hole was continuously cored, which produced an approximately 3" diameter rock sample. The continuous core extended from near surface to a depth which equaled or exceeded the depth of the lowest most seam to be mined. Coring depths ranged from near ground surface to between approximately 450 feet and 818 feet in depth. The samples were bagged, boxed and secured prior to transportation to the laboratory for analysis. Following collection of the rock core from each core hole, the core log was analyzed along with the core photographs to select lithologic similar rock. A data sheet was prepared by Colowyo consulting geologists detailing each rock layer. On the data sheet was the rock type, upper and lower depths, core thickness, depth and thickness adjustment to the downhole geophysical log, and the bag and box number the rock was located. This was transmitted to the analyzing laboratory for their use in breaking out the rock for analysis. Sample thickness ranged from approximately one foot to 15 feet and averaged 5 feet. A total of 619 discrete samples were collected and analyzed to characterize approximately 4,212 feet of overburden. All coal beds encountered in the continuous core, greater than one (1) foot in thickness, were removed for separate coal analysis. The following analyses and sample preparation were performed on overburden and coal samples: Physicochemical Analysis and Methods • pH, sat paste • Electrical Conductivity @ 25 C • Saturation • Texture • Ca (sat paste) • Mg (sat paste) • Na (sat paste) • SAR • Cation Exchange Capacity • Exchangeable Na • Exchangeable Sodium percent Collom — Rule 2, Page 16 USDA No.60 (21A) EPA Method M 120. 1 -meter,w/sat paste USDA No. 60 (2) ASTM D 422 Hydrometer EPA Method M6010 ICP EPA Method M6010 ICP EPA Method M6010 ICP calculation NH40ac, USDA No. 60 (19) NH40ac extractable, M6010B ICP Exchangeable Na/CEC Revision Date: 4/7/17 Revision No.: RN -07