2022-08-02_REVISION - M1977211 - Laserfiche WebLink

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® Sta ntecti M To: Tim Cazier From: Paul Kos CDRMS Denver Project/File: 2057288200 Date: July 15, 2022 Reference: Technical Revision Request for Pikeview Quarry M-1977-211 Mr. Cazier, Continental Materials Corp. (CIVIC) is in the process of reclaiming the Pikeview Quarry. The reclamation plan requires the placement of a buttress fill to stabilize and reclaim the mine. The backfill specifications currently limit the fill placement to 12-inch-thick compacted lifts. In preparing this Technical Revision (TR), CIVIC requests the maximum lift thickness be increased to 24 inches. To date, approximately 800,000 cubic yards of fill material have been placed and compacted. There have been 220 compaction tests performed on the fill, and all tests have demonstrated that the fill meets the project specifications except for one test. After further compacting the area, a second test confirmed the compaction met the project specifications. The compaction testing rate is currently one test per 3,600 cubic yards (cy)of fill placed, which exceeds the project requirement of one test per 5,000 cy of fill placed. In March, CIVIC, Stantec, and the construction contractor Brice Civil Constructors (BCC) performed a lift thickness compaction test to support this TR. Compaction tests were performed in field conditions by placing compacted fill in a single 36-inch-thick lift. The test area was separated from the active fill area to prevent interference or confusion with the routine operations. Compaction tests were taken from the test pads to determine if 90% or greater compaction was achievable, and the compaction was tested at depths of 18, 24, and 36 inches. The results for each test are summarized in Table 1 and demonstrate that the material was compacted to or above the project requirements. No lessening of compaction was noted in the field test inspections, and the deeper materials were visually competent. The compaction test results and photos from the day of testing are attached. The compaction tests were performed on 3-31-22 and 4-1-22. These tests provide the rationale and demonstration that 24-inch-thick lifts will meet the project requirements. While a 36-inch-thick lift was tested and passed, CIVIC does not plan to request a lift thickness greater than 24 inches. Table 1: Compaction Test Results from 36" Thick Lift Wet Density Moisture Content Dry Density % BCC Test# Inc-fZ % cf Compaction 18 in.Test 1 124 3.9 122.3 98 18 in.Test 2 118.8 3.7 115.1 95 24 in.Test 1 126.2 4.1 122.1 96 24 in.Test 2 127.3 4.1 123.2 96 36 in.Test 1 119.3 3.9 115.4 93 36 in.Test 2 122.9 4.5 118.4 94