GENERAL37456 - Laserfiche WebLink

Home Browse Search

' 3.0 EXTRACTIVE USE EXHIBITS ' 3.A Mineral Resource Analysis/Supply and Demand 3.A.1 Commercial Value of Deposit The rhyolite deposit to be excavated is shown in the Colorado Geologic Survey Report "Sand, Gravel and Quarry Aggregate Resources, Colorado Front Range Counties" (Figure 3.A.1(1)}. This document recognizes rhyolite located in Douglas County as afine-grained volcanic rock with good potential as an construction aggregate. This particular deposit has exceptional ' commercial value because of its architectural quality stone. The proposed Castle Rock Quarry site contains the only economically viable source of rhyolite in Colorado. ' The primary value of rhyolite is as an amactive building and landscape stone. It comes in numerous colors ranging from gray and tan to pink and purple. This wide variation in color is unique to building stone and makes rhyolite a desirable choice. The light weight makes handling ' during construction easier and delivery costs lower. Rhyolite has a history of being used for building stone throughout Douglas County and the Denver azea. 1 LJ 1 1 1 ~~ Rhyolite also has been used for riprap on some stream channelization projects. Heavier materials are sometimes more desirable in certain applications, however rhyolite has been successfully used in projects specifying grouted riprap. Also, rhyolite is used on a limited basis in drainage fields and as base material throughout the County. Colorado State Law (C.R.S. 34-1-304) requires populous counties to conduct a study of commercial mineral deposits and prepare a master plan for their extraction. This law contains factors for counties to use in evaluating deposits. These factors are also helpful in evaluating zoning applications for mineral extraction on private land and they are listed below. A section of the Statute directs the Colorado Geological Survey to identify and locate commercial mineral deposits in the State "according to such factors as magnitude of the deposit and time of availability for and feasibility of extraction". The resource map in the Survey's ] 974 report identifies the land contained in this application as a commercial deposit of volcanic rhyolite. 2. The deposit should have "potential for effective multiple-sequential use' ~.vhich would result in benefits to the landowner, neighboring residents, and the community. "fhe mining plan maintains the drainage patterns of the mesa top and will no'. cause flooding. By only disturbing 60 acres of the 1,828 acres leased, the neighbors and the community will continue to enjoy the rural character of the land. The proposed rhyolite production at the site will perpetuate the use of a historically and geologically significant product indigenous only to this area.