Marble - Colorado Geological Survey

29 million cubic feet or 2.5 million tons of resource.
CGS also believes that none of this
could be economically mined by open quarry
methods (Figure 7).
Banded Marble (Pbzm)
This variety outcrops stratigraphically above
the dark gray marble which was previously
mined and trends to the southern property line.
It is a coarse grained marble with alternating
bands of light to medium gray and light blue
to white. These bands are approximately one
inch in thickness. Another variety has a tan
coloration. This tan coloration may be a surface
alteration product caused by the weathering of
minute pyrite grains which appear ubiquitors
throughout this variety. No reserves have been
assigned to this due to pyrite inclusion (see
Figure 19).
CALCULATION METHODS
The evaluation procedure utilized in this study
has been specified in the contract between
USGS/U.S. Forest Service and CGS as a Discounted
Cash Flow, Rate Of Return (DCFROR)
method. This method is based on a comparison
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of costs to revenues taken over a period of time
such as the mine life with consideration given
to the cost of money and with the opportunity
for competing investments. The discount factor
utilized in the study was adjusted to reflect
risks inherent in an investment of this nature.
The value of the property is the present value
factored sum of the net profit or loss after taxes
and after the prudent investor has met his return
goals. This evaluation does not consider
the tax advantages that a mining operation
might yield to other, unrelated investments,
but that the proposed operation must be self
supporting. The calculation employed the commercial
software program $EE, Investment Evaluations
Corporation, Golden, Colorado. This
program allows the user to conduct an evaluation
from a corporate or individual standpoint
and calculates a sensitivity by up and down
grading the costs and revenues by increments
up to 20 percent. The $EE program was selected
for use because the senior author of this
report and members of the Forest Service are
familiar with the program, its improvement
over spread sheet DCFROR programs used in
industry, and how it follows the widely accepted
Figure 19:
Banded marble which
occurs throughout the
Colorado-Highland
property. The thin bedded
nature and abundance of
pyrite in banded (or
"zebra") marble render it
of no economic
importance.