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. • 11111111111111111111 � S � - O5� <br /> 999 <br /> Knight Piesold LLC 1050 Seventeenth Street, Suite 500 <br /> Denver, Colorado 80265-0500 <br /> CONSULTING ENGINEERS AND ENVIRONMENTAL SCIENTISTS <br /> Telephone(303)629-8788 <br /> December 19, 1997 Telefax (303)629-8789 <br /> YOUR REFERENCE splpoo let <br /> OUR REFERENCE <br /> Mr. Carl Mount R.CDVED <br /> State of Colorado <br /> Division of Minerals and Geology DFC 2 9 1997 <br /> 1313 Sherman Street, Room 215 <br /> Denver, Colorado 80203 <br /> Division of Minerals rs l5oology <br /> Re: Modified SPLP Test Results, Sleeping Giant Project, Northwestern Colorado <br /> Dear Mr. Mount: <br /> This letter transmits the results of the modified Synthetic Precipitation Leaching Procedure (SPLP) <br /> EPA Method 1312 for the Joker Mine ore and residue samples. The types of material tested were <br /> those likely to be exposed to the atmosphere for extended periods of time, such as in stockpiles, <br /> waste dumps, or pit backfill Three material types were tested: ore treated with an organic surfactant <br /> (LOC), ore treated with LOC and aged for six weeks, and rinsed residue from the pilot-scale leaching <br /> process. <br /> Because the three materials were all very fine-grained, a leaching test procedure using equal amounts <br /> of liquid and solid(such as the Meteoric Water Mobility Procedure) was not considered suitable, <br /> since decanting sufficient liquid for the leachate analyses was not possible. It was decided to use a <br /> modification of the U.S. EPA Method 1312 Synthetic Precipitation Leaching Procedure(SPLP)test. <br /> The SPLP uses a 20:1 liquid to solid ratio to assess the leachability of metals(and other parameters) <br /> from the material following an 18-hour agitation period. The test uses an artificial precipitation <br /> solution as a lixiviant, composed of reagent-grade water adjusted to a pH of 5.00 +/- 0.05 using a <br /> 60:40 mixture of sulfuric and nitric acids. <br /> A modification of the SPLP was used to increase the amount of material tested without increasing <br /> the size of the containers and roller apparatus necessary to run the test. Instead of using a 20:1 ratio, <br /> a 5:1 liquid to solid ratio was used. This modification results in a more concentrated end-product (by <br /> a factor of four) due to the greater mass of sample. The larger sample is also considered more <br /> representative. <br /> Testing was performed by ACZ Laboratories in Steamboat Springs, Colorado. Four SPLP tests were <br /> performed, one on each sample of material discussed above, and a duplicate test run on a split of the <br /> ore treated with LOC and unaged. The bottles containing the lixiviant and solid in a 5:1 ratio were <br /> continuously agitated for 18 hours, then removed from the bottle roller device. The samples were <br /> pre-filtered to remove sediment and the filtrate(leachate) analyzed for the parameters shown on the <br /> enclosed tables. <br /> MEMBEROF <br /> �:• AMERICAN CONSULTING Knight Piesold <br /> ENGINEERS COUNCIL GROUP <br />