APPCOR10646 - Laserfiche WebLink

Home Browse Search

-z- The first step in the reclamation operation is to backfill the open pits. Two pits will have to be backfilled with material from two overburden stock- piles. The equipment to be used to backfill the pits are Caterpillar 7738 trucks and 988 loader to fill the trucks. The following distances were measured from Map v-1 of the application: 1. Center of Spoil Pile 2 to the Center of Pit 6 = 1,600 feet 2. Center of Spoil Pile 1 to the Center of Pit 5 = 2;300 feet 3. Center of Spoil Pile 1 to the Center of Pit 6 = 2,600 feet A Caterpillar 988 B loader has a cycle time of 0.55 minutes (pg. 315, CH) and a bucket capacity of 7 yd3 heaped. The fill factor on the bucket would be ap- proximately 85$ for loose blasted material (pg. 296, CH). Therefore, a 9888 loader can place 5.95 yd3 in a truck each cycle. It would take 7 cycles to fill a 773 B truck (capacity 40 yd3) or 3.85 minutes. However, since the first Ioad can be dumped in the exchange time, it would take 3.3 Minutes to load a 7738 truck. The fixed portions of the cycle time for a 7738 truck (pg. 223, CH) are the load time (3.3 minutes), exhanae time (0.7 minutes), and the dump time (1.0 minute), for a total fixed time of 5.0 minutes. Using the nomograms on pages 239 and 240 of the Caterpillar Handbook, the following cycle times were determined for each haul distance, based on 4~ total resistance: Haul Distance Cycle Time 1,600 ft. 5.0 min. fixed + 0.9 loaded + 0.7 retom = 6.6 min. 2,300 ft. 5.0 min. fixed + 1.2 loaded + 0.9 retom = 7.1 min. 2,900 ft. 5.0 min. fixed + 1.5 loaded + 1.1 retom = 7.6 min. Two trucks per loader would be the most efficient use of the equipment. On a 1,600 foot haul, all equipment would be constantly workino. On any haul distance over 1,600 feet, the trucks would be the limiting factor (the loader would be idle for short periods) because truck cycle time is greater than two times the loading time. These cycle times will be used in the following reclamation cost estimate.