Laserfiche WebLink
3) OVERBURDEN MONITORING, IN PIT <br />Background <br />Since 1983, Colowyo has monitored overburden quality by taking <br />in pit samples ahead of mining and regraded area sampling behind <br />the mining advance. <br />Initially, in pit overburden sampling included Upper Y, Lower <br />Y, Upper X and Lower X truck/shovel lifts. The initial sampling <br />program provided sufficient information to drop the sampling <br />requirement for Upper X and Lower X and a commitment to selectively <br />utilize weathered material from Upper Y and Lower Y truck/shovel <br />lifts for the final regraded surface. This modification to the <br />sampling program was approved as T.R.-015 on April 24, 1990. <br />Colowyo has continued to sample the weathered overburden <br />material in the Upper Y and Lower Y truck/shovel cuts not only in <br />the main pit but Section it and Section 15/16 X seam pits as well. <br />Based upon the data presented in the 1992 Annual Reclamation <br />Report, a total of 187 samples have been analyzed from these areas <br />and show conclusively (with only a couple of anomalies) that the <br />quality of these weathered overburden zones continue to be the most <br />desirable for reclamation purposes. Data for the 1993 sampling of <br />Section 16 (see the attached Section 16 Overburden Analysis Table) <br />also continues to show the desirable nature of this spoil material <br />as well. <br />It appears that the data supports our conclusion that further <br />sampling of these overburden zones, Upper Y, Lower Y and section 16 <br />Pit serves no practical purpose. <br />Proposal _ <br />Based upon the data obtained from the Colowyo Overburden <br />Sampling program we propose to discontinue all in pit overburden <br />sampling ahead of mining. Colowyo will continue to utilize the <br />weathered overburden materials, shown to be desirable for <br />reclamation purposes, on the regraded surface behind the mining <br />advance. Colowyo will also, for the time being, continue the <br />current regraded overburden sampling program. We anticipate that <br />should the regraded overburden sampling program continue to show <br />positive results Colowyo will likely request that this monitoring <br />program also be terminated at some future date. <br /> <br />'f R-a ~ <br />