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~ III IIIIIIIIIIIII III ~ <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman SL, Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FA%:1303)832-8106 <br />December l I, 2000 <br />To: Jim Dillie ,~,~/ ~ ~./ <br />From: Harry PoseyS~-,7f <br />Subject: Test method for gyp/sum sludge; B;vIRI, San Luis Project, M-88-112. <br />DIVISION OF <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MIN ING•SAFETY <br />Bill Owens <br />Governor <br />Greg E Walther <br />E~ecunve Dnectur <br />Michael B. Long <br />Drci~inn Director <br />As you are aware, BMRI produces a gypsum sludge in their water treatment plant that <br />consists dominantly of gypsum with minor calcite. Although this sludge is currently being <br />trucked to landfills for ultimate disposition, at least one local rancher has asked to use the <br />gypsum from Battle Mountain, provided it is free of toxicants. To that end, the San Luis Field <br />Office of the NRCS has supported his plan. Gypsum is applied locally as a soil arhendment to <br />reduce sodicity; in soils, the calcium in gypsum exchanges with sodium, giving the soils a better <br />texture and lower sodium content. <br />BMRI has asked that the Division recommend a test to verify that the sludge contains no <br />constituents deliterious to plants. Although there are numerous standard soil tests, it would seem <br />that the most acceptable one would measure toxicity of those elements in the feed water that <br />appear to be of most concern, namely, manganese and copper. <br />Having consulted with Jim Finley of HSI-Geotrans and staff soil scientist, Tony Waldron, <br />it would appear that measurement of a DTPA extract might be best employed for this <br />examination. According to Soil Fertility and Fertilizers (Samuel L. Tisdale and Werner L. <br />Nelson, Third Edition, 1975, MacMillan Publishing Co., p. 332), DTPA <br />(diethylenetriaminepentaaceticacid) chelates or sequesters metallic ions, specifically iron, <br />copper, zinc, and manganese, and thereby mimics their availability to plants in soils. This test <br />can be modified to include other metals; however, considering the feed solutions t0 the water <br />treatment plant, this does not seem to be necessary. Other metal extractions procedures that <br />mimic plant uptake of metals in soils might also be used, provided the company has more <br />acceptable criteria. Consultation with the soils labs is recommended. <br />In summary, l would recommend that the gypsum sludge be tested for metals using a <br />standard DTPA procedure. Such tests can be run at the CSU soil labs as well as other private <br />commercial soil labs. <br />cc: Jim Stevens <br />Tony Waldron <br />Jim Finley, HSI-Geotrans <br />