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RESOLUTION
WHEREAS, it has come to the attention of the Board of County
Commissioners, Weld County, Colorado, that there is a need for a
subsidence study of mined-out areas in Weld County, and
WHEREAS, the Colorado State Geologist has recommended to
the Board that a geological survey should be made in Weld County of
mined-out areas and requested a contribution of Five Thousand Dollars
($5, 000. 00) from the County for this purpose, and
WHEREAS, there are no funds available for such study other
than those funds reposing in the regional budge of the Weld County
Planning Commission, and
WHEREAS,. certain funds have been set aside in the 1973 Planning
Commission budget for a flood plain study on the Big Thompson River,
and
WHEREAS, it appears that no progress nor commitment has
been made relative to such flood plain study in 1973, and
WHEREAS, the Board has determined that it would be in the best
interests of .the County to make available Five Thousand Dollars
($5, 000. 00) for a subsidence study of mined-out area in the County from
the funds heretofore earmarked for a flood plain study in the County.
NOW, THEREFORE, BE IT RESOLVED, by the Board of County
Commissioners, Weld County, Colorado, and it hereby authorizes and
orders Five Thousand Dollars ($5, 000. 00) of funds, heretofore earmarked
for a flood plain study, to be used to pay for a subsidence study of
mined-out areas in Weld County.
The above and foregoing Resolution was, on motion duly made and
seconded, adopted by the following vote on the 19th day of September,
A. D. , 1973.
BOARD OF COUNTY COMMISSIONE.RS
WELD��UNTY, COLORADO
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A l-(
ATTEST: ! 1) t t� 1- l
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Coun-y cor �r
and Clerk to the Board
i',, Z2 ,>•
,
Deputy County Clerk
AP-FRWED AS T FORM:
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T County 'Attorney
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CC: Acctg
Auditor
Planning Comm 7639
John Rol - State Geologist
JOHN D. VANDERHOOF �;., ^ I t JOHN W. ROAD
Governor . .�
Director
COLORADO GEOLOGICAL SURVEY
DEPARTMENT OF NATURAL. RESOURCES
254 COLUMBINE BUILDING - 1845 SHERMAN STREET O '
DENVER, COLORADO 80203 PHONE 892-2611
COUNTY OF WELD
,1 with the Clurk of le uoard
01 Cc.1u,•ty Co^imisslonerf
March 15, 1.974 141/aK 2 0 IQI
COUNTY CLlnK ANO lIrCONimfr
ay r r
Weld County Commissioners
Weld County Courthouse
Greeley, Colorado 80631
Gentlemen: RE: COLORADO GEOLOGICAL SURVEY STUDY
OF SUBSIDENCE IN THE BOULDER-
WELD' COAL FIELD
The Colorado Geological Survey is now commencing actual work on the coal
mine subsidence study which was described to county and other local groups
during planning stages last summer. The investigation is being performed
by the geological consulting firm of Amuedo and Ivey under contract to
our agency. We are responsible for planning and general supervision of
the study as well as liaison with residents and local government.
The study will involve a considerable amount of field work and interviews
with local residents, officials, maintenance supervisors, and others who
may have knowledge of past and present local events. Accordingly, we
are soliciting your cooperation and that of the area residents in aiding
our consultants to obtain the information and cooperation that will be
needed to efficiently conduct the studies. Members of the Amuedo and Ivey
firm who will be actively involved in the project will include: Mr. John
B. Ivey, Mr. Addison Myers, Mr. Doyle Scroggs, or other designated memberi
of the Amuedo and Ivey staff. We will keep you informed of progress on
the study which should be completed within the next six months. If you
have any questions or pertinent information relating to the study, please
call or visit our office.
Sincerely,
John W. Rold
Director and State Geologist
/ \ • -_
William P. Rogers \'
Engineering Geologist and Project
Coordinator
WPR/crs GEOLOGY
STORY OF THE PAST . . . KEY TO THE FUTURE
X0700$-74
PROJECT OUTLINE FOR PROPOSED COOPERATIVE STUDY TO EVALUATE SUBSIDENCE IN UNDER-
MINED PORTIONS OF THE BOULDER-WELD COAL FIELD OF COLORADO
JUSTIFICATION. The study area encompasses approximately 150 square miles that
has been mined for coal at various times and places during the past 100 years.
At the present time, only three active mines remain (in the vicinity of Erie), and
the area has returned essentially to an agricultural economy. The area is now
in the path of urbanization because of its location near the major centers of
Denver, Boulder, and Greeley. Currently impacts related to Front Range growth
are being felt adjacent to the old mining towns of Louisville, Lafayette, Erie,
Dacono, Frederick, and Firestone. From inquiries received by our office and the
county planning offices, it is obvious that much of the land in unincorporated
parts of the area is being purchased or optioned on the prospect of future urban
development. It is well known that subsidence over old mine workings has occurred
in many parts of the area and there are indications that such settlement is con-
tinuing. The proposed study is intended to more accurately define the extent of
mining and various other physical factors that may control the extent, time or
severity of subsidence. The information obtained will be extremely useful to
state and local government as well as the general public in arriving at sound
land use practices for the study area.
FUNDING AND PARTICIPATION. The Colorado Geological Survey received $5,000.00 in
the budget for FY 1973-1974 to conduct an evaluation of subsidence in this area.
It was specified that the funding was contingent upon receiving a 1:1 or better
match from other sources. Our estimate is that it would require a total budget
of at least $17,500.00 to complete the study. A grant of $5,000.00 was received
from Weld County in October of 1973. Following discussions with Mr. Joseph B.
Smith (Colorado Liaison Officer, U. S. Bureau of Mines) , the Colorado Geological
Survey received a grant of $7,500.00 in cooperative funding from the U. S. Bureau
of Mines.
Page 2.
PROJECT ELEMENTS OF PROPOSED STUDY.
1. Compile detailed maps showing the extent of mining_. Probably scale of map:
one inch equal to 2,000 feet. Sources of data: Records of Colorado Bureau of
Mines, U. S. Bureau of Mines, U. S. Geological Survey, mine owners' and operators'
naps and records.
2. Maps showing depth to mined horizons. The coal beds occur in faulted and
tilted strata, this together with a rolling surface topography makes the depth
to mined coal seams quite variable. This data will be determined and presented
on special maps depicting "depth of cover". Sources of data as above, plus USGS
topographic data.
3. Physical characteristics of strata overlying mined coal. It is well estab-
lished that the rate, extent, and amount of subsidence is determined to a large
extent by the character of geologic strata between the mined out area and the
surface. This is related to the stratigraphy, structure, topography, and level
of erosion. These data will be determined as accurately as possible from existing
sources including USGS and proprietary.
4. Details of Mining will be tabulated, plotted and presented on maps. Items
included will consist of: (A) Geometry of extraction, i.e. room and pillar vs.
long wall or other; (B) Percent of extraction (areal); (C) Total thickness of
extraction, areas of multiple-layer extraction; (D) Time of extraction, by five
or ten year increments.
5. Inventory of past and present subsidence problems. Including: (A) Field and
aerial studies, photographic studies; (B) People-Agency inventory of both past
and currect problems that are probably related to underground mining.
b. Evaluation and Analysis of all of above for significant criteria. An evalu-
ation of the total data will be done and a text written explaining the general
Page 3.
findings of the investigation.
7. Finally, a subsidence hazard map will be prepared which will classify lands
of the area with respect to the probability of future or continued subsidence.
This is not expected to be "final solution" to the subsidence problems, but will
serve as useful guidelines in area planning and land use decisions.
PERSONNEL AND SUPERVISION. Supervision o£ the study will be by the professional
staff of the Colorado Geological Survey, including Mr. John W. Rold, Director
and State Geologist; and Dr. Wm. P. Rogers, Engineering Geologist. The actual
work will be done by a consulting firm under supervision and guidance of the
Colorado Geological Survey staff.
TINE SCHEDULE. Work on the project will commence as soon as funding can be
finalized and personnel obtained. We would intend to have study under way as
soon as possible, with the final report expected by no later than December 31, 1974.
William P. Rogers
Engineering Geologist and Project Coordinator
Colorado Geological Survey
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