Laserfiche WebLink
<br />Ron Thompson <br />Page 3 <br />04/30/99 <br /> <br />Water level increased significantly at overburden well NM-22. This well is in the <br />vicinity of two other wells that are likely domestic wells for ranchette development. <br />SF-2, completed in the overburden 3000 feet southeast of the mined area showed <br />over 350 feet of decline between 1994 and 1996, but now appears to have <br />stabilized and may be slowly recovering. One possible explanation for the <br />significant decline and subsequent slow recovery in this well may be the connection <br />to the fault inflows encountered in the eastern development workings of the mine. <br />Large fault inflows resulted in abandonment of this area of the mine, and until <br />flooding is complete, inflows may cause a continued drawdown and slow recovery <br />of the water level in SF-2. The Division will continue to review semi-annual water <br />level data to verify recover of all of the bedrock wells. <br />Bedrock ground water quality sampling requirements were dropped from the <br />monitoring program due to the distance from the mined area. Previous sampling <br />had indicated an improvement in salinity due to gradient reversal caused by mining <br />drawdown. As the mine workings flood, the natural groundwater gradient to the <br />north-northeast will be re-established. Water quality will be monitored in the mine <br />workings through the GEM series of wells on an annual basis. <br />Flooding of the workings is assumed, as current data from the three GEM sites <br />have not returned measurable water levels or acquisition of a sample. Analysis <br />done by the Division estimates that a measurable water level will likely result at the <br />GEM-2 and GEM-3 sites in May of the year 2000. GEM-1, at the old Jeffrey intake <br />fan site near the mine portal, will be the last site to show flooding, although a small <br />amount of flooding has occurred at this site due to it's location in the mains. Water <br />measured at this site is probably spilling to the north into the extensive area of <br />longwall mining north of Highway 12. GEM-1 is also the highest elevation of the <br />mine floor of the three GEM wells that are completed in the workings. Field <br />parameters indicate a conductivity of 540 umhos/cm and a pH of 7.3, which is <br />normal for ground water in the area. Temperature is approximately 52 degrees F <br />which is also normal for ground water outside of geothermal areas. <br />Alluvial water levels, as indicated in wells PAW-5 upstream of the mine and PAW-6 <br />downstream of the mine, continue to show normal variation due to seasonal <br />influences and no impact to alluvial water levels can be identified at this time. <br />Alluvial water quality remains slightly more saline than the surface water which <br />recharges the alluvium, but is within an acceptable range for all known and current <br />uses. Quality changes due to mining are not apparent. <br />Sarina and Seeo Survev <br />The spring and seep survey was conducted August 5 through August 28, 1 998 in <br />accordance with the approved plan. Spring #1 in Cherry Canyon was observed <br />with a flow of 2 gpm. Flows at springs #2-7 in Alamosito Canyon remains at <br />