PERMFILE69486

• Permit No: M1979070
• IBM Index Class Name: Permit File
• Doc Date: 4/21/1979
• Doc Name: REGULAR 112 PERMIT APPLICATION FORM
• Media Type: D
• Archive: No

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December 13, 1976 • •
File No. 73-2-1
EXHIB/T I
Mr. E. A. Rossum St~/L S
302 Big Thompson Canyon ,Road
Loveland, CO 80537
Subject: 14ineral and Gravel Analysis, 41est Half of the
Northwest Quarter, Section 17, Township 5 North,
Range 69 4lest, Larimer County, CO
Dear Mr. Rossum:
As you have requested, we have investigated the subsoil strata at
the above described tract to determine the feasibility of mining
the gravel aggregates.
FIELD AND LABORATORY EXPLORATION
Four test pits were dug wit'.
Test Boring plan, Figure 1.
capacity of the backhoe. A
course gravel layer exposed
performed in the laboratory
on Figure III.
i a backhoe at the locations shown in the
The maximum depth explored was 13', the
representative sample was taken from the
in Test Pit 2. A gradation analysis was
on this sample; the results are shown
SITE CONDITIONS
The portion of the site explored was the flood plain of the Big
Thompson River. The gravel deposits found lie in a bow of the river.
The site slopes to the east and upward from the river bed to the
south. An out cropping of bedrock is visible on the site at the
extreme southeast corner.
SUBSOIL CONDITIONS
The area of the flood plain is covered by 18" to 7' of fine silty
sand. The western portion of the site has 7' of alternate layers of
cobbles and silty sands overlying the gravel layer. The gravel layer
is a well graded, dense gravel. Approximately 80% is larger than the
H4 sieve and is smaller than 8" top size. There is an occasional
large (18" diameter) boulder. The depth of this layer is unknown;
we conservatively estimate it to be approximately 20' in depth. At
known locations in the Big Thompson gravel producing area, it varies
from ,15' to 30'. This gravel layer thins out as you approach the
hills to the south and appears.to be only 2' thick at Test Pit If4.
The gravel consists of approximately the following composition:
60% granite, 24% Gneiss, 9% quartzite, 3% sandstone, and 4% miscel-
laneous type of rock. The rocks are hard unweathered, well rounded.
There is no evidence of lime deposits and it appears that the gravel
deposits would be an excellent source for aggregates to be used in
concrete and other construction materials.
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