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We~ceni Atle~ International ..,. ~..,..ror. TEST PROCEDURE CORE LABORATORIES Humidity cell tests can be run on groups of up to twelve samples. A representative 200.0 gram portion of the air-dried, minus 10 mesh sample is placed in each cell. Cells are-then sealed and air-line hoses are securely fastened. Testing consists of a seven day cycle which is repeated for a total of eight to ten weeks, depending on client needs. Each weekly cycle starts by feeding dry air to the humidity cell for three days. Humidified air is then fed to each cell on days four through six. On day seven, 200 mis of deionized water is added to each cell and allowed to soak for one hour. After one hour, the sample leachate is drained into the collection beaker. Sample leachates are 0.45um filtered and analyzed for pH, conductivity, sulfate, iron and acidity. Additional parameters can be analyzed, if requested, although sample leachate volume is a limiting factor. OPERATING SPECIFICATION3 An air flow rate of five to eight liters per minute is maintained through each cell during both dry and humidified air cycles. Hose clamps are utilized to aid in equalizing flow rates. Approximately 110 to 150 mis of vaporized water pass through each cell during the three day humidified air cycle. Ambient temperatures range from 60 to 80 degrees fahrenheit during testing. Sample material is left undisturbed for the duration of testing. ANALYTICAL RESULTS Analytical results for weekly sample leachates generated from each humidity cell are reported using a standard format. In addition, graphs of appropriate analytical results versus time (normally pH, cumulative sulfate and cumulative acidity) are also reported. DISCUSSION Kinetic testing used to predict acid mina drainage is a relatively new concept. Humidity cell testing is designed to measure the rate of oxidation and weathering of various soils, rock and overburden samples. The normal operating specifications described above can be modified to best match a particular environment. Analytical results can also be reported in a format which better meets the needs of the project or client. rH S~s~rss oo-r~sn~~nronanc sconnn•e ~~m~s•socnmws•a uoW aes•rvsums•na mnvn~suodna oy dN Ce•mror.r~os••.cww•sro cannw~ns~us•m,s •soon n•swa TSO• rn• •myppanOq a• o0~rvpn1 •.d••seo •mu•~~ m, o•n map•~wi a Cd• l.•oa~cno Con UOMaia~n w W^M ronfOpWP~M W m•su ro wvnrny u nn•••nuro~s oorsn o• ^a^aa 4 'o T• doaucw~ry. wow. ow••nons a va~•oun•ss ro.•W. a snr w. p•s. cwi a om« In~n••s~ Yooart,. «•n n una .n cwrcron ~m rn•cn sucn noon n uwe d •n•o moon ~a acr •••sm rm•navw