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Msrch 1993 A'aaticiry Evelueuen • 1 <br />• ACZ loc. (ACZ) completed a geotechnical stability analysis of the existing coal refuse pile ar the Energy Fuels <br />Coal Iuc. (EFCn Southfield Mire and submitted it to the Colorado Mined Land Reclamation Division (CMLRD) <br />0o January 14, 1992. The CMLRD reviewed and approved the analysis, stipuhtting however, than EFCI complete <br />samplirg and testing of refuse materials to determine material plasticity, evaluate test results relative to the stability <br />analysis, develop a plw to monitor refuse plasticity, a~ establish criteria and designs for selective placemem of <br />high plasticity rcfuse if indicated. <br />The followirtg proposed evaluation plan represents the initial step in addressing dte CMLRD stipulations. Upon <br />completion of plasticity sampling, testing, evaluation, and development of the monitorirtg and placemem plans and <br />criteria, all relevant information, including the 1988 and 1991/1992 stability evaluations will be cotuolidated, <br />organized and submitted to CMLRD in the form of a technical revision application. <br />1.0 Nastidty Sampling and Testing Nan <br />EFCI proposes to collect and test 8 to 12 refuse samples m determire a representative plasticity range for the coal <br />refttse materials previously and curready placed on the coal refuse stockpile. Samples will be collected from both <br />the existing stockpile and the preparation plant fice refitse discharge. <br />Approximately 6 to 8 refuse samples will be collected from the existing reftLSe stockpile. EFCI will collect samples <br />fiom various areas of the pile in order to obtain a good representation of any potential variances in material <br />consistency and characteristics. To the extent possible and in order to avoid redisturbattce, samples will be taken <br />from areas which have not been topsoiled and reclaimed. If samples are collected in a previously topsoiled area, <br />special care will be taken to insue that the sample is collected below the topsoil replacement horizon and to avoid <br />mixing topsoil materials with the sample. Approximately one quart samples will be collected at each sampling <br />• location a~ samples will be bagged, labelled and shipped directly m a qualified laboratory for resting. <br />Approximate sample locations will be Doted on a map, sire specific conditions, including samplirg depth, and <br />variations in refttse material color, composition or coasisterey, will be noted in a field book, each sample site will <br />be photographed for future referettce, and the approximate time period durirtg which the material was placed will <br />be noted if possible. <br />Approximately 2 to 4 refuse samples will be collected from the preparation plant fire refuse discharge. The <br />primary purpose in collecting refuse samples directly from the preparation plam fire refuse discharge is to verify <br />coasisterey between plasticity test results for raw and in-place samples from the same time period. EFCI is <br />currently in the process of shiftirtg production from the west main entries (Jack O'Lantern Seam) to the south sub- <br />maias (Red Arrow Scam). EFCI plans to obtain plam refuse samples both before and after this transition to <br />characterize any variances in plasticity between reface from the two coal seams presently beirtg mired. Plartt <br />samples will be collected from the fine refuse discharge, bagged, labelled and shipped directly to a qualified <br />laboratory for testing. To the extern possible, plant samples will be identified relative to the source area(s) for the <br />wrrespo>biog coal production run. <br />Atterberg limit tests will be run on all samples to determire liquid limit, Plastic limit, and plasticity index. The <br />procedures outlined in American Society for Testing and Materials (ASTM) Standard D~318 will be utilized for <br />limit testing. <br />Both the plastic and liquid limit tests utilize material at or slightly above natural moisture comem, which has been <br />screened to produce a test sample of material passing a No. 40 standard sieve. For the liquid limit test, the sample <br />is molded imo a flat sample cup and a standardized tool is used to cut a groove in the sample. The sample cup <br />is rhea mounted on an impact bed which subjects the sample to 25 impact blows by droppittg the cup from a <br />specified height onto dte fixed impact bed. The liquid limit is the moisture content at which the sample deforms <br />• with closure at the bottom of the groove under the influence of the repetitive impacts. Sample moisture is adjusted <br />by addition of water or drying and remixing until the liquid limit is clearly defired, then sample moisture at the <br />limit is determined by standardized methods. <br />c:wsryrj~a.pm <br />M,+~+9'! 0.,r <br />