Laserfiche WebLink
~~,/ CORE LABORATORIES <br />Wlastern Atlas <br />International <br />1 <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 />interpret. <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 />i 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 to the cells <br />(humidified air). During testing, cells are placed on wire racks with <br />~~ glass beakers located below the drain of each cell for collection of <br />leachate (Fig. 2j. <br />TEST PROCEDURE <br />Tests can be run on groups of up to twelve samples. 200.0 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 fur three days, <br />~ followed by three days of humidified air. On the seventh day, 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, and acidity. <br />This cycle is repeated for 8 to 10 weeks. <br />cM1e ana,ys~s, opmrons or vae~waN,ans coma,neE in Inn report are 6asetl upon oDServahons e,q ma,enai suppentl oy me u~en, ,o~ wnose e.u~s~+e antl cmuaennai use nm report nas <br />ynen mdOe Yne mlar0,91a1gns Or oOmWns etpreSSW rapgnM lnl OeSI ryEB^BM OICore labwmw~ae Corn LiOOfer0~e5 assumes no re5pM5~0ilay anO maa95 na wananlym rnOrCSenld~ <br />lions. n. press or ,mpl:~, es 10 Ina protluclrvey. woper operenons or proM1leMBMSS M1owwrer of any oil, gaz, coal or olner m~nerai. D•ope^Y. well o• SeM ~n cOnnec,gn wan wn~cn such <br />~epOn ~s uswler reneo coon Inr any reaspn wne,soevM. <br />