Laserfiche WebLink
began to seep out. Solution flowed along the edges of the drain tile to more permeable areas, but <br /> because the topography was so flat some of the solution spilled off liner. Since the release, the liner in <br /> this area has been extended up the hill side and other measures have been put in place to prevent this <br /> from occurring again. <br /> The modification/scenario in this TR is very different from the referenced 2012 event. The proposed <br /> pipe is solid smooth-wall HDPE and is open to the atmosphere at the discharge end which is over 150 <br /> feet below the inlet. The pipe will not seep, leak, or burst from over pressuring. The two flat areas in <br /> question are small benches; one is located on the south side of the HGM platform and the other is <br /> located where the SGVLF bench access roads intersect. The pipe will not be flat in either one of these <br /> locations. Actual slope dimensions combined with the limited flexibility of the pipe will ensure the pipe <br /> is sloped downhill in the upper section near the High Grade Mill. The pipe will be partially buried on <br /> the lower segment to maintain a downhill gradient.Unlike Phase 5,drainage around both of these areas <br /> is sufficient and all drains directly towards the center of SGVLF. <br /> The HGM solution is used in the leach circuit at the HGM, some of the solution is recycled in the <br /> process, and the excess solution is currently added to the AGVLF. In regards to the chemistry issue <br /> previously observed, the precipitation issues at the AGVLF are the result of many different solutions <br /> being mixed and continuously circulated through the AGVLF,causing isolated areas were precipitation <br /> occurs. The HGM solution will not be recycled through the process multiple times and no other <br /> solutions will be mixed in causing changes in chemistry; it will only be HGM discharge. The chemistry <br /> of the HGM solution is such that it will not cause precipitation within the SGVLF. When it was stated <br /> that this solution is similar to the leach solution CC&V was referring to pH, alkalinity and cyanide <br /> concentrations. <br /> B. Modifications to the approved plan (p. I)—Please clarify whether the proposed four inch HDPE pipeline is <br /> to be smooth or corrugated on the inside. <br /> CC&V Response: The pipe will be solid smooth-wall HDPE DRIL <br /> C. Modifications to the approved plan (p. 2) — A statement is made to the effect that maintaining a similar <br /> solution application rate for the proposed infiltration gallery (as compared to the rest of the pad)so as to not <br /> adversely impact the stability of the pad. Please quanta the two application rates so the DBMS can is not <br /> required to assess a qualitative comparison. <br /> CC&V Response:Normal leach application rates are in the range of 0.003-0.006 gallons per minute <br /> (gpm) per foot (ft)2. Infiltration rates proposed in this TR will be on the order of 1 gpm/ft2. This <br /> application rate is approximately 1/101h of the application rate for the current injection wells and is less <br /> than 1/1001h of rates demonstrated to be stable in the Geotechnical Stability Report submitted in TR-79. <br /> Should you require further information please do not hesitate to contact Tyler O'Donnell at 719.689.4056 or <br /> Tyler.O'Donnell(&newmont.com or myself at 719.689.4055 or Meg•Burt(a),newmont.com. <br /> Sincerely, <br /> Meg Burt <br /> Senior Environmental Manager <br /> Cripple Creek&Victor Gold Mining Co <br /> MB/tvo <br /> Ec: T. Cazier—DRMS <br /> 2 <br />