Laserfiche WebLink
` '~,' <br />' CORE LABORATORIES <br />~ vvbseen, aotles <br />International <br />~~~ HUAiIDITY CELL TESTS <br />' INTRODUCTION <br />Tests used to predict the formation of acid mine drainage fall <br />into two groups. They include static tests which measure the amounts <br />' of acid producing materials and acid consuming materials, and kinetic <br />tests which attempt to model the acid producing and consuming processes <br />that occur in the natural environment. Humidity cell tests fall under <br />the latter group. Results from static tests are relatively simple to <br />~ interpret but may not be representative of naturally occurring <br />reactions. Humidity cell tests are a more realistic model of reactions <br />in the natural environment but results may be more difficult to <br />i interpret. <br />i <br />' METHODS ~. <br />SAMPLE PREPARATION <br />Samples are first air dried at room temperature for 24 hours or <br />until a stable weight is obtained. Air dried samples are then crushed <br />to minus 10 mesh (2 mm) and thoroughly blended. Air-dried, crushed <br />samples are stored in plastic bags. <br />TEST APPARATUS <br />^ The test cells are plastic containers with tight fitting lids. <br />Each cell is 2.75 inches high, 7 inches long, and 7 inches wide with an <br />air inlet in the top center of the lid and a drain fitting in the <br />bottom corner (Fig. 1). A series of 12 cells are connected by equal <br />lengths of 0.5 inch diameter plastic tubing to a regulated source of <br />' compressed air. A 6.5 gallon glass carboy fitted inside with plastic <br />tubing and two air stones and half filled with deionized water is used <br />to generate humidified air. Compressed air can feed directly to the <br />;' cells (dry air) or through the carboy first and then t~> the cells <br />(humidified air). During testing, cells are placed on wiree racks with <br />glass beakers located below the drain of each cell for collection of <br />leachate (Fig. 2). <br />TEST PROCEDURE <br />Tests can be run on groups of up to twelve samples. ::00.0 gms of <br />prepped sample is placed in a cell. All cells are sealed and hoses <br />securely fastened. A seven day cycle is initiated in all the cells. <br />First, dry air is passed through the sample cells for three days, <br />' ~' followed by three days of humidified air. On the seventh aay, 200 mis <br />of deionized water is added to each cell and allowed to soak for 1 <br />hour. The leachate is then allowed to drain into a collection beaker, <br />filtered, and analyzed for pH, conductivity, sulfate, a:~d acidity. <br />This cycle is repeated for 8 to 10 weeks. <br />1 <br />'~ Tne analrsn. [p~nb^s w mlvprelaLplS coniairo0 m ins report eye oaseO upon opwwaions arW maiend suppLw nr i^e chum mr .nme v. ouv.u a~U o.n.u..,n..e u+n Inn n.pon neb <br />DMn maW TM ~nlerpe~algna p OpnYaa sapaiYereprlanllM DCStiWYilTanl Dl Core ldGpalp MS.CWe LAEW atpnes eswrMS MlefponS~DiM1ly ana me.es np .. ru WnV O~rnp~e ]an B. <br />Ipp, lapW p Mrp1MU. O Ip IM prMYLIMI), pCQV pr~laltlN p poinadenefa I~paerel OI yly pl, 1]L5, (p.l p caner m.MIY, popa.lr. will W siOC ~n Mmy,;I~Jn xR9 wmCn :~Cn <br />' repprl u ueeG p reneE upon b enr reeam ~neuparsr. <br />