PUB00013

• Year: 1985
• Title: Estimated Use of Water in Colorado 1985
• CWCB Section: Water Conservation & Drought Planning
• Author: David W. Litke and Cynthia L. Appel
• Description: Water-Resources Investigations Report 88-4101
• Publications - Doc Type: Brochure

operations. Data were compiled for this category for water-source type,
water-supply method (assumed to be entirely self supplied), and water-
disposition type. Four types of mining activity were investigated for water
use: coal mines, other mines (principally hardrock), sand and gravel
quarries, and oil producers. Each of these will be discussed separately in
the following paragraphs.

There were 33 active coal mines in Colorado during 1985 (Colorado
Division of Mines, written commun., 1987); 10 of these were surface mines and
23 were underground mines. Production was 17.3 million tons, and most (83
percent) occurred in Moffat, Routt, Gunnison, and Pitkin Counties. Water-use
data were acquired from personnel at 15 of these mines, which accounted for 78
percent of production, and data were interpolated for the remaining mines
using coal-production data. It is estimated that 3.03 million gallons per day
of ground water and 2.70 million gallons per day of surface water were
withdrawn for coal mining use. Of this quantity, 1.03 million gallons per day
was consumptive use, of which about 57 percent was due to evaporation of
coal moisture. In surface mines, water is used primarily for dust control,
washing of equipment, and domestic use by miners. Surface runoff impounded in
sedimentation ponds was not considered a water use, but evaporation from these
ponds was considered a use. In underground mines, the principal use of water
is lubrication for drilling and dewatering of mines.

There were about 150 active hard-rock mines in Colorado during 1985
(Colorado Department of Mines, written commun., 1985), and copper, gold,
molybdenum, silver, and uranium were the principal products. Most of these
mines are small, intermittent operations. Of the estimated 2,700 persons
employed in these mines, 2,000 were employed by the six largest operations.
Site-specific water-use data for 13 of the largest mines were acquired through
direct contact or by examination of mine operation reports. Water use for the
remaining mines was estimated using water-use ratios for Colorado developed
from 1982 Census data (U.S. Bureau of the Census, 1985), which reported an
average of 5,500 gallons withdrawn per day per employee, of which 75 percent
was ground water and 10 percent was consumptive use. About 16.71 million
gallons per day of ground water and 24.87 million gallons per day of surface
water were withdrawn by hardrock mines during 1985, and about 3.71 million
gallons per day was consumptive use. Most of the ground-water use consists
of mine dewatering; most of the surface-water use is the result of natural
drainage water entering mine water supply or discharge systems. Most of the
hardrock mining water use occurred in Lake, Clear Creek, Teller, San Juan, and
Ouray Counties.

About 20,000 permits for sand and gravel operations have been issued in
Colorado (Dick Stensel, State Engineer's Office, oral commun., 1987). It was
not possible to investigate all these operations. The major water use
associated with gravel pit operations is water evaporation from ponds.
Estimates of the total surface area of these ponds, their location, and the
quantity of evaporative water use from these ponds were made based on
information obtained from the State Engineer's Office. It was estimated that
8.93 million gallons per day of ground water was withdrawn and consumptively
used during 1985. Most of this use occurred in the valley of the South Platte
River or in the valleys of its tributaries along the northern Front Range.

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