Laserfiche WebLink
Matthews, Berry <br />Page 2 <br />October 7. 1998 <br />Based on a review of the data presented in the AHR there is no discernable impacts to surface water <br />quantity due to mining operations at either Munger or McClane Canyon, and no significant trends <br />in surface water quality are identifiable throughout the year. However, previous yeazs water quality <br />data are not presented for comparison (see discussion below). There was a substantial increase in <br />total suspended solids in third quarter 1997 which appears to be due to an increased sediment load <br />from an intense storm. <br />Although there has been no mine inflow or discharge from either mine this year, groundwater has <br />been encountered at the McClane Mine in the past, as predicted by the McClane Canyon PHC. <br />Infiltration to the mine appears to be from a perched aquifer in the area of the mine and from surface <br />water infiltration. The AHR states that a piezometerdown gradient from the mine has always been <br />dry. This probably indicates that groundwater is confined to a localized area. However, [o <br />substantiate this, well construction information for the down gradient piezometer would need to be <br />reviewed. Based on the data presented and the fact that there are no users of groundwater in adjacent <br />areas to the mine, there is essentially no significant impact to groundwater quantity resulting from <br />the mining operation. There are no identifiable adverse water quality trends for the water yeaz for <br />the groundwater monitoring data presented. However, previous years water quality data are not <br />presented. The AHR states that results of groundwaterquality sampling aze consistentwith previous <br />years. <br />One potential concern noted that is not addressed by the PHC predictions, is the possibility for <br />perpetual discharge from the McClane Mine. In previous years water has been pumped from [he <br />mine and a dewatered zone created in the coal. The area of the mine that experienced inflows is now <br />reportedly sealed and water is flowing into the sealed area at an estimated 3.9 gallons per minute. <br />Without being familiar with the mine site, it is difficult to determine the potential for dischazge from <br />the mine once the sealed azea becomes filled with water. Will it discharge down dip into another <br />portion of the underground workings or will it potentially discharge at [he surface? If this potential <br />exists, then we might consider updating the PHC portion(s) of the permit document. <br />General Comments <br />2. <br />3. <br />There is no surface water sample location upstream of Munger Canyon Mine, only a <br />downstream location (SW-3). <br />"there are no laboratory analyses reported for groundwatersamples. It appears that only field <br />parameters were collected. In addition to the field pazameters reported, our Rules require at <br />a minimum total iron and total manganese for groundwater. <br />No flow information was provided for SW-5 for third quarter 1997 <br />- /~~a/~,/"o~y <br />/~+y K r r <br />~S;.lr. R.ew.-o~~tCY <br />~ a.~9 te~ <br />