Laserfiche WebLink
<br /> <br />' CO i.ORA DO GJES TMOREf,AND, INC. <br />Orchard Valley Mine - Perrnit Application <br />Colorado MLRD/OSM Joint Review <br />Rydrology, Groundwater <br />Because of the confusion surrounrliny the possible existence of groundwater <br />in the permit and adjacent areas, further study is needed. Much of the <br />information for thrr yrounr7i,•ater study can probahly be generated using <br />in-house information and brl a site inspection by CWI staf;~ of theiz~ groundwater <br />consultant. <br />Colorado Westmoreland, Inc., needs to provide the following information: <br />Drill Logs of exploratory and core hales in the permit and adjacent areas. <br />Ber'a use the logs arc• geophysica.t logs, it would assist the analysis if the <br />Logs were interpreted by CIJI and the type, location, and thickness of the <br />strata were noted on the logs. <br />Several East-West and North-South cross-sections through the permit and <br />adjacent areas showing the geology down to and including the first aquifer <br />and other coal seams below the lowest coal scam to be mined. The location <br />of the cross-sections should be shown on a plan view of the permit area. The <br />drill logs used to draw a cross-section should be plotted on the cross-section. <br />These cross-sections can be used to locate fault zones and associated <br />fracture zones and con tinuou.s sandstone beds or other strata which could <br />act as aquifers. <br />If the cross-sections indicate that there are strata or zones which can <br />be aquifers, the existence of water can perhaps be determined from in-house <br />sources. These in-house sources include: Information developed during drilling, <br />abandoned mine workings adjacent to the permit area, the existence of springs, <br />seeps, of wells in the area, especially if these are found downdip (north) of <br />the mine plan area; the results of testing Pad No. 47 as a water source; the <br />existence of heavier vegetation along the outcrop of various strata, again, <br />especially if they outcrolr downdip of the mine plan area; and, past experience <br />during mining. If fault and fracture zones encountered during past mining are <br />known to be extensive, both vr.rticalhJ and horizontally, and it can be shown <br />that they intersect the strata which are potential aquifers, then the rate, <br />duration, and quantitiy of groundwater flow or lack thereof, from these <br />zones can provide information concerning the existence of groundwater. The <br />springs and seeps can also indicate the existence of other alluvial aquifers <br />similar to the one CWI i.s currently using as a water source. <br />The 92 springs and stockpondsabove t)ic mine area, mentioned in the application, <br />need to be clearly located on a map or maps, preferably of 1 inch = 500 feet <br />scale. The map should clearly differentiate between springs and ponds. <br />The location, extent, and piezometric surface subsurface waters within and <br />adjacent to the permit area must be mapped and described; such groundwater systems <br />must be delineated using in-house infrirmationrby field studies, or by drilling <br />exploratory wells, if necessary. <br />'4. ~ ,iA I i. <br />