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I F(,FNr) FLAN , �' I� 1990 - 95 - 1995 -2000 2000 -2005 t IN PROGRESS RECLAMATION PLAN Terraces will be completed from the top down. The first terraces to be completed will be covered with soil from quarry expansion areas, to a depth of 12 inches or more and revegetated with grasses and native shrubs. Later terraces will be covered with "quarry fines" and truck -ramp material to a depth of 12 inches or more, mixed with aero- bically digested sewage sludge (or equivalent organic fertilizer) at the rate of 20 tons or more per acre, and revegetated. u� 21 e Colorado School of Mines Research Institute March 12, 1975 Mr. Dale Ream Cooley Gravel Company 4800 Wadsworth P. O. Box 5485 Denver CO 80217 Dear Dale: r' O BOX 112 • GOLOFN COLORADO 80401 PHONE (3031 279 2581 CSM CSMRI Project C41006 The purpose of this letter is to provide you with some background dis- cussion relating to the proposed final pit layouts for the Morrison Quarry. As you may recall, the Institute was engaged by Cooley in January of 1972 to provide initial and final pit layouts, monitorblast- ing, and provide other technical support. The Morrison Quarry is located in Jefferson County about a mile south and west of the community of Morrison. Access is by paved road ap- proximately due west from Highway 285. The initial pit layouts ^r epared in the Spring of 1972 were based upon data provided by Coolp- Gravel and the State of Colorado Mining Laws in effect at that time. The basic mining plan called for a bench height of 80 feet and a bench •,Ldth of 40 feet. The bench faces were designed originally not to exceed an 80 degree slope in rock. Basic geologic data were meager in the quarry area. Therefore, a program of bench development and monitoring was recommended. Two 80 -foot by 40 -foot benches were developed along a portion of the south side of the quarry. Operations then ceased in this area, and the benches were observed visually for a period of two years. in late 1974, these benches were examined and found to be stable. Bench slopes were found to be approximately 69 degrees. The proposed pit layout prepared for Cooley Gravel in late 1974 incor- porates the 69 degree backslope and 40- foot -wide by 80- foot -high benches. This results in an overall pit slope of approximately 49 degrees. 7000 GBoo G(od0 G400 6 Zoo 0 COLORADO SCHOOL OF MINES RESEARCH INSTITUTE Mr. Dale Ream Cooley Gravel Company March 12, 1975 Page 2 Several considerations regarding the development of the final pit wall are essential when examining the layouts. The first of these is that the law requires a stable slope. The term "stable" is interpreted to mean that no catastrophic failures, such as landslides, may occur. The slope design shown in the layouts is adequate for the conditions developed in the test benches. These include competent rock and shallow depths. The slope shown is probably the steepest slope which may be used in the final quarry walls. In those areas of the pit where geologic structures, or incompetent rocks, are found, a flatter slope will be required. It is recommended that these areas be defined as mining progresses, and that their effects on final pit configurations be evaluated. This will require continued ex- amination, evaluation, and recording of pit slope activity. The accumulation of adequate data through experience, and test work where needed, will allow for the modification of the pit wall so that a stable slope is ensured. As quarry operations proceed, benches will be developed according to the mining plan. Drilling and blasting patterns for these benches will be de- signed to maximize rock fragmentation and quarry production. Such blasting tends to fracture the rock below the bench level and also back into the adjacent wall rock. Therefore, it is recommended that all final benches be developed with presplitting or smooth wall blasting techniques. Such techniques are well developed and allow the development of stable slopes such as those visible in the mountainous portions of Interstate 70. I trust that the foregoing discussion is adequate for your needs. If I may provide any additional information, please do not hesitate to call on me. Sincerely, Iink es Director Mining Division /cjm 2c? 40o Goo Boo ioao /Zoo /4ao 16100 /Bas Z000 SECT /ON A -A (Sfo. 4 f oo� zoo o zoo 400 SCALE OF FEET FINAL RECLAMATION PLAN Item (a) The final pit will be a series of steep cuts 80 feet high with a face slope of less than 800 between terraces 40 feet wide. (See Section A -A) The terraces will be landscaped with grasses and local shrubs. The cuts will remain as they are. Roads that will not receive continuing use will be obliterated and vegetated. tern (b) The use of surrounding company lands for open space will be compatable with the Mount Falcon Open Space lands and the Denver Mountain Park unit that now adjoins the pro- perty to the north and west. Item (c) Site will The maintained by the applicant after reclamation. Item (d) Most of the top soil on the area that has beer, quarried is mixed with "quarry fines" and "crusher fines" and now serves as truck ramps wjithin the quarry. Soil yet to be moved will be taken directly to complleted terraces. Truck ramp maternal will be re- claimed later. Item (e) Reclaimed a3reas and their vegetation will be maintained at least 3 years to assure their success. Maitnemance will include halting soil eromion, if any, and reseeding or planting to assure a vegetative cover. Permit Number 0r/ Class: Permit O - _Secli_o /Exhibit_��_�y /��,/ Class:GRevis1011 Type /Seq: Class: O Report O HydrooGeneral - _--- - - - -_ - - Doc Type: Application (Coal only) ❑ amd O En /orcement ❑ Inspection RECEIVED FEB 13 1976 RECLAMATION SECTION ro:n. Cent. of gahl/]) Ritior .ee COOLEY GRAVEL COMPANY MORRISON QUARRY SITE AND RECLAMATION PLAN 2ZO� RECLAMATION DETAILS Leonard Rice Consulting Water Engineers Inc 7envar Albuquerque DESIGNED TRACED RM CHECKED HB Joe No 19474 JULY 1975 IIIIIIIIIIII IIIIIIIIIIIIIIIIIIII VIII III 0017612 -- -- a ISHEE7 4 OF B __'