GENERAL55061 - Laserfiche WebLink

Home Browse Search

J S ~, ~ ~ a~~ Trapper I~iining Inc. III IIIIIIIIIIIIIIII Bnx 187 999 Craig, Colu~ado 81626 (303) 824-4401 {' ~'' July 1, 1983 ~it~~~..`~~~~~ ,!l7t 51983 Mr. Mike Savage Colorado Mined Land Reclamation Division 423 Centennial Building 1313 Sherman Street Denver, Colorado 80203 Dear Mlke: '[JlNED LA~JD RECLAMA710N Colo. Dept. of Natural Resources Please accept the following explanation including the enclosed plan map and illustrative cross section as our plan for verification of the 25Y, overburden swell factor which we have projected for the Trapper Mine. We intend to use photogrammetric methods in combination with our own historical survey data for this verification. I have outlined four study areas as shown on the plan map which cover regraded areas of our three active pits. We will construct north-south cross sections within each study area on 150-200 foot centers. This will enable the cross sections to coincide with the individual cut 'toe' lines where we haoe adequate elevations to construct a profile of the pit floor. With the four study areas combined we will have 43,750 feet of cross sections through a total area of 188 acres. The enclosed cross section will serve to illustrate and explain our swell calculation method and to show how the aerial survey data will be combined with ~, our pas[ pit surveys [o produce the composite sections. The aerial survey company that does our surface mapping project this summer (Aug. or Sept.) will also develop cross sections in the areas indicated on the plan map. These cross sections will include the regrade line and the original 'topo' line, with the regrade line based on the _new aerial mapping and the original 'topo' line digitized from our 1975 topographic maps. After receiving the cross sections, we will produce the two lower lines from our survey records. The 'pit floor line' is the pit bottom after all overburden, partings, and coal seams have been removed and the 'top of coal' line represents the total coal ~[hickness (all mineable seams combined) above the pLt bottom. As and Ab, as defined on the cross sectional drawing, will then be digitized by computer methods and [he swell factor calculated by [he following formula: X Swell Factor = [(As/Ab)-1J 100. The aerial mapping project should start in August or September when our summer reclamation work is complete. With a 60-75 day turnaround time between