Laserfiche WebLink
RULE 2 PERMITS <br /> <br />South Taylor/Lower Wilson – Rule 2, Page 14 Revision Date: 6/4/25 <br /> Revision No.: MR-264 <br />Exploration Test Borings <br /> <br />Exploration test borings have been conducted within the South Taylor/Lower Wilson mining areas and <br />have been used for the following purposes: <br /> <br />Identifying Location of Subsurface Water - Since most of the exploration drill holes were dry, the <br />circulation medium for most exploration drill holes drilled within the mine areas was compressed air with <br />water and foam to lift the cuttings to the surface. Drilling mud was used when heavy fracturing or burn <br />areas were encountered. Several drill holes throughout the area encountered minor amounts of <br />groundwater; however, all of the data obtained to date by Colowyo and the USGS have indicated that <br />groundwater occurrences in the Williams Fork Formation in the area are not continuous but rather are a <br />series of perched systems of limited lateral and vertical extent. Information on groundwater occurrence is <br />provided in Section 2.04.7. <br /> <br />Characterizing Physical Properties of the Overburden - The overburden material, which is removed as <br />a part of the mining operation, consists mainly of mudstones, siltstones, and sandstones. Generally, the <br />mudstones will have a relatively high erodibility and compaction factor, while sandstones and siltstones <br />will have low erodibility factors and low to moderate compaction. Because of the variable lithology and <br />lenticular nature of the strata in the permit area and the variations in the mining techniques (dragline, <br />truck/shovel), it is difficult to determine an actual value for the swell of the overburden; therefore, the <br />overall swell of the overburden material was estimated to be approximately twenty (20) percent. <br /> <br />Evaluating Geochemical Properties of Overburden - Chemical analyses of overburden and interburden <br />strata in the areas to be mined are provided in Exhibit 6, Item 6. The ongoing overburden sampling <br />program at Colowyo described in Exhibit 6, Item 4 of the existing permit document has confirmed earlier <br />estimates of the geochemical properties of the overburden identified by exploratory drilling. A summary <br />of overburden geochemistry is presented in Table 2.04.6-3 and the relevant borehole locations are shown <br />on Map 11B. <br /> <br />This section presents the results and interpretations of geochemical tests performed on overburden <br />material samples from the South Taylor/Lower Wilson pit areas. The purpose of these tests is to <br />determine the chemical composition and assess the acid-forming, toxic-forming, or alkalinity-producing <br />potential of overburden material within the South Taylor/Lower Wilson pit areas. This section describes <br />the methods used in collecting overburden samples for testing, the types of tests performed and the tests <br />results. In addition test result were compared with appropriate overburden guidelines to assess the <br />acid-forming, toxic-forming, or alkalinity-producing potential of overburden material within the South <br />Taylor/Lower Wilson pit areas <br />