2013-05-16_HYDROLOGY - C1981014 - Laserfiche WebLink

Home Browse Search

maintains that this represents a perched aquifer, but that does not explain how that water entered the casing since the only known opening would be the bottom end of the casing. A water test on a much smaller scale than George used to show that the MWNW communicated with the mine works was carried out on SF- 87 -07, and this showed that the water level increased and then decreased to pre -test elevation. The unresolved question is why is there a measurable water level in this well? This well is above a different panel than the MWNW, but it is only about 780 ft. west of MWNW. Is the 2 North Submains panel full of water? While the MWNW might have communicated with the mine void in 2012 at the time of the water injection test, does it still communicate today? What is the effect of the multiple seals of the various panels on the water levels in the mine? What is the effect of the interconnections of Southfield with other old mines such as the roof fall in the 1 North Submains that allowed viewing of the old mine workings high above? What is the location of the roof fall? Is the old mine the Zenith or the Liberty? Randy Acre told us about this event in the 1990s although no one will comment recently on the story or provide a more exact location except to say that it was impossible to seal the connection to the old mine. Other potential paths for water exchange between old mines and Southfield are the exploratory drill holes for which there are no plugging data to confirm correct sealing, open drill holes that are not part of the monitoring plan, and drill holes that cannot be located because of lack of a permanent marker. Southfield undermined and pillared under the Thompson Well listed as abandoned on Map 12, although the Colorado Division of Water Resources shows a water well permit number of 22948 -F along with a 2008 change of owner - address. If abandoned, why was a change of owner - address submitted? The elevations of the water in SF- 87 -07, SF- 87 -09, MW65, and the point of water discharge to the surface in Second Alkali Creek were all about equal in 2012. Is that a coincidence? When SR65 was drilled in 1983, it penetrated old mine workings of the Black Diamond void with water at -527 ft. After casing this hole the water level was 155 ft. The first water levels reported as part of the regular routine monitoring measurements were between -240 to -258 ft. from 1983 to 1988 at which time there was a precipitous drop of about 40 ft. to a level of about -280 ft. The level has remained at this point since then. This drill hole intercepted the old mine workings in the top seam and was completed to a total depth below the Southfield seam ; SF -87 -07 is entirely below the top seam strata and SF -87 -09 was drilled through a solid pillar of the top seam. The monitoring point on Second Alkali Creek, SA1, is too far upstream to monitor the surface discharge point which is at 38d17'57.72 "N 105d10'07.49 "W (NAD83). Yet, all four water levels are about equal elevation with the surface discharge point being the effective limiting elevation for the water levels in the three drill holes and the old mine voids. The Southfield permit section 2.05 discusses the potential effects of Southfield mining upon the flow of Newlin Creek and Second Alkali Creek. It has a long discussion of possible impacts to Newlin Creek, Hardscrabble Creek, and the Arkansas, but it dismisses any possibility of impact to Second Alkali Creek. A complete diversion of the Newlin Creek watershed flow to Second Alkali has never been considered by anyone else.