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_, <br />«~-~f ~~} <br />", -`~~,^'„ ~III'llllllllllll'IICOLORADO DIVISION OF MI •S <br />t~ ;i`~~. ~~ DEPARTMENT OF NATURAL RESOURCES <br />~' ' ~ 1845 Sherman Street, Denver. Colorado 80203 Telephone 892-3401 <br />Norman R. Blake Deouiv Commissioner of Mines <br />RiclTard D. Lamm <br />Gnvc~nor <br />February 14, 1975 <br />To: Norman Blake <br />From: Bob Campbell !~,(~e <br />Subject: Asphalt Paving - Ralston Operation <br />On January 29, 1975 I attended a hearing before the Jefferson County Board of <br />Adjustment in Golden, Colorado regarding Asphalt Paving's request for an early <br />hearing on the results of their testing, and for the Board to determine if they <br />had fulfilled the conditions set forth in a resolution from the June 27, 1974 <br />hearing. <br />As you will recall the Board of Adjustment at the June hearing granted Asphalt <br />a year's time for further testing and environmental studies until July 22, 1975. <br />There was to be core drilling only, test blasting carefully monitored, and rec- <br />lamation including revegetation of a previously mined area on the south end of <br />the proposed operation. <br />Ptr. Keller of Asphalt Paving, together with various consultants, presented the <br />results of their testing since the June hearing. Their test blasting showed <br />the following: <br />1. Their blasting monitoring showed a velocity of 0,002 inches per <br />second, (They stated structural damage could occur above 2"/sec- <br />ond.) <br />2. The rate at the water department tunnel should be below 0.5"/sec- <br />ond and is well below this figure. <br />3. Professor Romig of the Colorado School of Mines stated that the <br />risk of triggering earthquakes was very small, <br />4. The results of the monitoring for sound pollution showed them to <br />be below the present 80 dB requirements. <br />Asphalt planted recommended grasses on the south slope in August 1974. <br />The antifreeze in their water bars for dust control will be anon-contaminant. <br />Various other detailed results of their tests are available in the Asphalt Pav- <br />ing Company's reports. <br />A spokesman for the Land Use Commission asked the Board to defer a decision to <br />a later date. <br />~; <br />The City of Golden stated that the problems of truck traffic need to be resolved <br />as well as the problem of blasting concussion. <br />