PERMFILE139399 - Laserfiche WebLink

Home Browse Search

No injury or diminution to any surface water resource occurred duriny 19,i.i as the result of underground coal extraction at the Orchard Valley Mine. Colorado West- moreland Inc. commenced monitoring all hydrological features located..,~_,the...._.__~- approved permit area and the Paonia "D" Tract during 1983. Monitoring will con- . tinue until baseline information is generated, at which time the emphasis will • shift toward areas where mining is scheduled. Stream flow data collected from several ephemeral drainages should indicate no impacts from mining occurred during 1983, because no significant drainages were undermined (refer to Tables 3 and 4). Both quantity and quality remained virtu- ally unaffected. Springs located within the permit area boundary originate from collrrvium land- slide debris material. Table 5 which presents discharge and quality data indi- cates no impacts as a result of underground mining upon these resources. Simi- larly, Table 6 portrays monitoring data concerning surface water storage ponds. No impact due to mining was evident during 1983. Brooks (1983), states, "Over- burden thickness of greater than 600 ft. is necessary to attenuate surface subsi- dence effects" and no springs or ponds were undermined within that zone. Steven's Gulch well field data, Table 7, indicates mining adjacent to this important resource has not adversely affected either water quality or quantity during 1983. Here again, no mining has taken place below this well field. train to adout facilities data suggests this auxiliary function has no impact upon the quantity or quality of water flowing in the North Fork of the Gunnison River • (refer to Table 8 and AVF Study submitted to the Division). r,~ Although mine inflows are present at the Orchard Valley Mine, they are of a small magnitude and usually short duration. Table 9, however, represents analysis of a "grab sample" obtained from amore significant inflow event. The water chemistry suggests the inflows at the Orchard Valley Mine originate as nontributary ground- water and will be periodically discharged with no adverse effects. Mineability and logistical considerations necessitated substituting DH-1O for OH-58 as a wrater quality monitoring yell. Colorado Westmoreland Inc. believes that the shallower depth and better access will enable monthly monitoring, as portrayed in Table 10. The similar chemistry of water analyzed from DH-10, Farmer's Mine, and 2 1/2 West inflow indicates a similar origin. Due to flow meter malfunctions, the data presented in Table 11 is approximated. Production rates from 1982 to 1982 differed minimally. In fact, Orchard Valley production reached one million tons on the same date for each year. The est+- mates of imported water consumed within the mine should be valid. Table 12, Nod? 22 data, indicates no degradation of ambient o-,ater quality as the result of discharging effluent from the sev+age treatment plant, in compliance with NPDES standards. -3-