Laserfiche WebLink
Although we have assumed that Tower Lake will be full to the ground surface for <br />the purposes of this global stability calculation, we have not addressed slope <br />erosion from flooding or overtopping of the lake. Neither have we addressed a <br />"piping" failure whereby underground piping of fines carried by ground water <br />flowing from the lake to the pit dewatering trench causes volume loss (soil) at the <br />bottom of the mine face and subsequent cave-ins, and potential blow-outs. If you <br />mine close to the 25 ft mark, someone knowledgeable should watch for piping <br />and there should be a contingency plan to buttress any area experiencing piping <br />with 3/4-in stone. <br />We understand that your intent is to not mine to closer than approximately 50 ft to <br />the property line in this area to ensure the integrity of your neighbor's ski lake. <br />We agree that this is a prudent plan. <br />Please contact me or Alan Howard if you have any questions regarding this letter <br />or if we can be of any additional assistance with this matter. <br />Best regards, <br />BRIERLEY ASSOCIATES <br />Bill Zietlow, P.E. <br />Attachments <br />2