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1*lark A. Heffner, Ecologist • III IIII IIIIIIIII III ~dtrecla adon planning <br />37 East Colorado Avenue <br />Denver, CO 80210-3105 Visual impact analysis <br />(303) 722-9067 (Voice and Fax) Documenrary photography <br />May 17, 1999 <br />Berhan Keffelew <br />Division of Minerals and Geology RECE'V <br />Rm 215 Centennial Bldg. Et~ <br />1313 Sherman St. MAY 1 <br />Denver, CO 80203 9 1999 <br />Division of Minerab & l;eolo9Y <br />RE: Responses to Adequacy Concerns letter of Apri127, 1999. <br />Permit: M-99-004 Table Mountain Quarry <br />Dear Berhan: <br />Following are our responses to your adequacy questions for this operation. The responses are <br />arranged in order of the questions you asked, with a modification of format. <br />Mining Plan - <br />Concern A, Part l: Methods of reducing the rock content in the rocky soils. <br />Response: There are basically two methods envisioned at this time that should <br />work well to remove a significant part of the rock content in the rocky soils. Other methods may <br />be discovered through experimentation, but these two will be worked with first. <br />Method 1: Screening -The soil could be screened and that would remove a <br />great deal of the rock, perhaps more than is desirable unless a very large screen size was used. The <br />problem with screening soil is that if the soil contains remaining [wigs, slicks, branches, and roots <br />from any woody material originally growing in the soil these have a tendency to plug the holes in <br />the screen. The result is a pile of material not all that different from what was put on the screen; <br />it's just better blended which really isn't what is desired. So, if the soil is quite clean of woody <br />materials screening would work. Because there is a great deal of woody material growing on the <br />soils that are to be salvaged, the screening method probably would not produce the desired results. <br />But it could be used where there is little woody material remaining. <br />Method 2: Sorting - Basically, this method is the same [ha[ is used to sort big <br />rocks from small rocks in blasted material. Simply skimming the top of the material with a dozer <br />blade will separate the large rocks from the small rocks. When working with soil this method <br />separates the large rocks from the soil and smaller rocks. This is more in line with what is desired. <br />We do not want to remove all the rock as that helps with soil drainage and creates a more <br />favorable invasion environment for trees and shrubs. Although this method can sometimes also <br />