1992-05-18_REVISION - C1991078 - Laserfiche WebLink

Home Browse Search

2.05.4 (2 ) (b) • In round numbers the amount of material, measured in cubic yards, that will be handled to reclaim the mine at the worst case condition is as follows: Topsoil Spoil Spoil Spoil From From From From Highwall Stockpile Stockpile Ridges Reduction Area 1 25,000 81,000 56,000 -0- Area 2 75,000 20,000 58,000 89,000 Pond B 14,000 The 25,000 cubic yards of topsoil in Area 1 repre- sents 18.6 acres of untopsoiled area using the 10 inch topsoil replacement depth. In Mining Area 2 the topsoil replacement depth is 20 inches. The 75,000 cubic yards of topsoil in Area 2 therefore represents 27 .9 acres of untopsoiled area. The topsoil in the Pond B area is just that topsoil salvaged during the Pond B construction which represents a disturbed area of about 3 acres. The total area to be topsoiled and reclaimed in this analysis is ( 18.6 + 27 .9 + 3) 49.5 acres. The haul distances for the spoil and topsoil from the stockpiles and the average grade for both are as follows: Mining Area No. 1 Mining Area No. 2 Pond B Topsoil Spoil Topsoil Spoil Topsoil Haul Distance 2400 ' 900, 3600' 3000 ' 300 , Grade 2 .2% 2.9% 2.7% 2 .5% -6.7% The following discussion forms the basis for the above reclamation estimate: Spoil and Topsoil It will be assumed that an equipment spread of two 651E scrapers and one D-9 push cat will be used to haul the spoil and topsoil. Cycle times and productions are as follows. The CY/Hour production figure assumes two scrapers, a 50 minute work hour, a payload of 34 .6 cubic yards of topsoil and 34 .6 cubic yards of spoil. The cost per cubic yard is calculated using an hourly rate of $150 for the D-9 and $175 for the 651E scrapers. Load/Dump Haul Return Total CY/Hour Cost/CY Topsoil Area 1 1.3 1.6 1.0 3.9 444 1. 13 Spoil Area 1 1.3 0.6 0.5 2.4 721 0.69 Topsoil Area 2 1.3 2.2 1.4 4 .9 353 1.42 Spoil Area 2 1.3 1.8 1.2 4.3 402 1.24 • 2.05-171 May 1992 i