Laserfiche WebLink
<br />Terrell Johnson 2 <br />Spoil Spring Quality 8/85 <br />October 18, 1985 <br />8507D 8507H 8508E 85086 8508C <br />Pond F Spoil Springs SW Site Spring East OB Pile #2b <br />S rin at Pond A #12 Spring of OB#2b Underdrain <br />TDS(mg/1) 4100 2280 - 3820 4160 <br />EC(umhos) 3840 2640 3760 3720 3990 <br />Sulfate(mg/1) 2730 1430 - 2320 2470 <br />The total contribution of these springs to streamflow is difficult to <br />determine since flow sites have not been established by the operator. <br />However, our field measurements showed the springs contributing several <br />-, hundred gallons per minute. The quality of the springs is variable but <br />comparable to other mines in the 20 Mile Park. TDS and sulfates have elevated <br />levels while metals and trace elements remain low. The TDS levels are at or <br />slightly below the concentrations predicted by MLRD from the CYCC leach tests, <br />as depicted below: <br />Predicted Spoil Quality Based <br />on CYCC Leach Test Data <br />Years of Leaching <br />Quality of Spoil Water(mg/1) <br />Years 10 Years 20 Years 51 Years 73 Years <br />500 3800 3000 1500 640 <br />The information on the springs is significant in that CYCC did not predict <br />springs would develop in the backfilled spoils. CYCC incorrectly predicted <br />that the bedrock strata downgradient from the backfilled pits were permeable <br />enough to transmit all the spoils water. This would mean all spoils water <br />would bypass Foidel Creek and flow into the regional deep bedrock ground water <br />system with eventual discharge to Fish Creek. The error in the prediction <br />appears to be an overestimation of the flow capacity of the bedrock caused by <br />an error in modeling (see also Mine #3). A quick recalculation of the spoil <br />and bedrock permeability follows: <br />Spoils discharge predicted by CYCC = 1330 ac-ft/yr. <br />Bedrock discharge predicted by CYCC: Q=K(i?)a <br />Q=(2.9gpd/sgft)(1?)(1,060,000sgft) <br />Q=3443ac-ft/yr <br />This appears to indicate that the bedrock can transmit over 2 (two) times as <br />much water than the spoils. However, using a hydraulic gradient taken from <br />CYCC's piezometric maps and properly incorporating it into the flow model: <br />Bedrock Q=Kia <br />=(2.9)(0.09)(1,060,000)=309ac-ft/yr <br />