Nov. 6, 2023

On-Site Quarry and Aggregate Processing Plant Essential Aspects to Construction

Just south of the main dam along the western edge of the reservoir’s high-water line sits the on-site quarry and aggregate processing plant, two of the most essential aspects of the project. Over the four years of construction, the on-site quarry will produce 12 million cubic yards of material for use in many different areas of the site, with only about 15 percent of that going through the aggregate processing plant. 

Material from the quarry is used throughout the project site, including roads, dams (main dam and saddle dam), inlet/outlet tunnel and spillway. To keep up with production the quarry equipment fleet includes: 

  • 12 100-ton CAT 777 haul trucks 
  • 2 6015 CAT excavators 
  • 2 992 CAT loader 
  • 395 CAT excavators  
  • D9 and D10 CAT dozers 
Backhoe loading Catepillar 777 truck with rock from quarry

The sedimentary rock in the quarry is considered waste and was removed to reach the good granitic rock underneath. The wasted rock is used for temporary, non-critical work in various places on site to build roads, berms, etc. 

Daily blasts in the quarry keep production on schedule. At peak production, the quarry supplies about 62,000 tons of material per day, making it one of the largest mining operations in Colorado. Once material is blasted, it is inspected and graded by on-site geologists and then delivered either directly to the main dam, the aggregate processing plant or occasionally wasted if poor rock conditions are observed. Each load that comes out of the quarry is carefully planned to go exactly where it is needed and is processed to the correct specification. 

Having both the quarry and the temporary aggregate processing facility on site minimizes the impact to the community and keeps truck traffic in the area to a minimum. Additionally, the removal of more than 300 vertical feet of material from the quarry will ultimately provide approximately 3,800 acre-feet of additional water storage in the finished reservoir.