Rocky XI


November 1, 2008

Rocky’s home undergoes numerous additions as quarry expands during its lifetime.

by Bill Langer

For the past 11 months, this column has been following events in the life of Rocky, a 1.8-billion-year-old rock I rescued from a quarry in Morrison, Colo. The Morrison quarry has been actively mining and crushing Rocky’s relatives, granite and gneiss rocks, since 1971, when the Cooley Gravel Co. started a 350-ton-per-hour crushed stone plant. The operation began on 560 acres of land with a 50-year supply of granitic rock resources.

By 1973, the Morrison quarry had become one of the top three producing quarries in Colorado. That same year, the Colorado legislature officially recognized that urban encroachment on aggregate resources in the greater Denver area of Colorado had become a serious issue. The legislature passed House Bill 1529, which declared that the state’s commercial mineral deposits were essential to the state’s economy. The act also declared that those mineral deposits should be extracted according to a rational plan calculated to avoid waste and cause the least practical disruption to the ecology and quality of life of the citizens.

However, actions taken by some counties to implement H.B.1529 were designed primarily to protect citizens from mining and generally worked against the protection of mineral resources. Efforts to develop new quarries in the late 1970s developed strong public opposition, and attempts to open new operations regularly were thwarted by permitting authorities. In 1981, the U.S. Department of Labor pointed out that H.B.1529 was a failure and that the availability of aggregate resources in the Denver area continued to decline because of zoning regulations driven by environmental and visual concerns.  There has not been a permit issued to open a new crushed stone quarry in the greater Denver area in more than 30 years.

Expansion became the way to go. During 1978, a permit was granted to Cooley Gravel Co. to develop the central quarry (the quarry filled with water in the accompanying photograph taken during 2004), just south of the original (north) quarry (the quarry in the foreground). In 1990, a permit was obtained to allow 24-hour operations and deliveries, which allowed the quarry to become one of the main suppliers of aggregates for the construction of the Denver International Airport. In 1994, the town of Morrison annexed the quarry into its town boundary, which was followed, in 1995, by the granting of a permit to allow the quarry to expand into a new south quarry operational area (the area being cleared).

Reserves in the north quarry operation at Morrison were exhausted in June 2008. Shortly thereafter, a high-capacity pump pipeline between the central and north quarries was completed. The north quarry has been developed as a water storage reservoir for the town of Morrison, with a final design capacity of about 1,500 acre feet. (As a rule of thumb, one acre foot is considered to be the annual usage of one suburban family.) About 300 acre feet of water that had been stored in the central quarry since 2004 has now been pumped into north quarry. The central quarry is to be backfilled with overburden from the south quarry, which will eventually create a level platform for a new stocking yard and a possible new plant site.

Poor Rocky won’t recognize the ol’ homestead!

Much of the information for this article was provided by Adrian Charters, U.S. Geological Services Manager, Aggregate Industries.

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