Feb 282017
 

We have a free 8.5- x 11-inch (pdf) geologic map of Colorado containing Geo-Whizology of Colorado on the reverse side.

Free 8.5- x 11-inch  map of Colorado geology along with Geo-Whizology

Free 8.5- x 11-inch map of Colorado geology (front) along with Geo-Whizology (back)

Of course, we’re a bit biased, but we think Colorado has magnificent geology and it is beautifully displayed for all to see. The state holds many of the biggest, the best, the first, and the most diverse:

For instance, did you know: Continue reading »

Feb 172017
 
IS-79 Colorado Mineral and Energy Industry Activities 2015-16 (cover)

The current annual Colorado Mineral and Energy Industry Activities report 2015-16 is now available. Following up on the 2014 report, this report, based on 2015 production data, sketches a comprehensive overview of Colorado’s mineral resource production. Of note is the fact that total value of mineral and energy fuels production in Colorado for 2015 is estimated to be $13.43 billion, a 29% decline from the $18.8 billion production value in 2014. The decline was caused primarily by a precipitous decrease in oil and gas market prices which provide 70% of Colorado mineral resource revenue. Oil and gas production actually registered at all-time highs of 127.6 Mbbl and 1,709 Bcf, respectively.

Nonfuel mineral production — including metals, industrial minerals, and construction materials — posted a modest 3.9% increase in revenue. Increased production of crushed stone, cement, and sand and gravel aggregate accounted for the increase. With a 2015 production of 21,790 metric tons of molybdenum from two mines, Colorado is the largest molybdenum producer in the U.S. Although just one mine in the state publicly reported gold production in 2015, Colorado remains the third largest producer of the metal in the U.S. as it was in 2014.


Citation: Cappa, James A., Michael K. O’Keefe, James R. Guilinger, and Karen A. Berry. “IS-79 Colorado Mineral and Energy Industry Activities 2015-16.” Mineral and Energy Industry. Information Series. Golden, CO: Colorado Geological Survey, 2016.
Feb 062017
 

With all the precipitation in the Rockies this year (we’re at +153% normal snowpack at the moment), we thought we would re-release a publication that highlights at least one important aspect of Colorado snowfall — that is, the significant danger of avalanches. The Snowy Torrents: Avalanche Accidents in the United States 1980-86, compiled and written by Nick Logan and Dale Atkins and illustrated with Larry Scott’s fine pencil drawings, was first published in 1996. We still have a few hard-copies available and, because of that, yes, we do charge for the PDF download. However, Larry went back and re-made the PDF from the original publication file, producing a file that is far better than the rather poor digital scan we had offered previously.

The volume details 146 oft-times harrowing stories surrounding avalanches, the lives they claim, survivors and witnesses, along with assessments as to what happened, why it happened, and what could have been done to prevent loss of life and/or property. The authors are never judgmental, and their clear-eyed accounts contain a wealth of wisdom that will add to the knowledge-base of any winter backcountry enthusiast.


Citation: Logan, Nick, and Dale Atkins. SP-39 The Snowy Torrents: Avalanche Accidents in the United States, 1980–86. Special Publications 39. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1996.
Jan 302017
 

Introduction

The earth’s surface can subside because of underground mining when rock is removed at depth. Although subsidence can occur due to hard rock mining, this article only considers the effects of coal mining.

When coal is extracted underground, gravity and the weight of the overlying rock may cause the layers of rock to shift and sink downward into the void left by the removal of the coal. Ultimately, this process can affect the surface, causing the ground to sag and crack and holes to form. Merely an inch of differential subsidence beneath a residential structure can cause several thousand dollars worth of damage.

Subsidence can happen suddenly and without warning. Detailed investigations of an undermined area are needed before development occurs to resolve the magnitude of the subsidence hazard and to determine if safe construction is possible. While investigations after development can determine the extent of undermining and potential subsidence, often, existing buildings cannot be protected against subsidence hazards. The cost of remedial measures is often extremely high. Continue reading »

Jan 162017
 

On solid ground — that’s how many of us think of good old, stable earth. So it’s disconcerting when the ground moves out from under us in any way.

Because of our environment, history, and geology, Colorado has conditions where ground movements can costs millions of dollars in annual property damage from repair and remediation, litigation, required investigations, and mitigation. There has been recent attention to swelling clay soils and heaving claystone bedrock, and the media has helped publicize these problems, which are predominant along the Front Range. But that’s only half the story. Geologic hazards in Colorado also include ground that sinks. Ground subsidence and soil settlement pose significant hazards in Colorado in many areas throughout the state. A variety of causes, some human-made and others inherent to the geology and geomorphology of Colorado, cause these sinking problems. Continue reading »

Jan 122017
 

At the end of the 19th and beginning of the 20th Century, some of the first settlers of the plateau region of western Colorado along the Colorado River, and the Uncompahgre and Paonia river basins, looked to fruit crops for their livelihood. The semi-arid but moderate climate was well suited for fruit orchards once irrigation canal systems could be constructed.

But serious problems occurred when certain lands were first broken out for agriculture and wetted by irrigation. They sank, so much in places (up to four feet!) that irrigation-canal flow directions were reversed, ponding occurred, and whole orchards, newly planted with fruit trees imported by rail and wagon at considerable expense, were lost. While not understood, fruit growers and agriculturists began to recognize the hazards of sinking ground. Horticulturists with the Colorado Agricultural College and Experimental Station (the predecessor of Colorado State University) made one of the first references to collapsible soil in their 1910 publication, Fruit-Growing in Arid Regions: An Account of Approved Fruit-Growing Practices in the Inter-Mountain Country of Western United States (pdf download). They warned about sinking ground and in their chapter, Preparation of Land for Planting, made one of the first recommendations for mitigation of the hazard. They stated that when breaking out new land for fruit orchards, the fields should be flood irrigated for a suitable time to induce soil collapse, before final grading of the orchard field, irrigation channels excavation, and planting the fruit tree seedlings. Continue reading »

Jan 112017
 

Regarding the Colorado Geological Survey (an article appearing in the Mining Reporter, March 1907):

We note that one of our contemporaries, in recently commenting on the University bill creating a State Geological Survey of Colorado — the bill reported favorably on by the joint Senate and House mining committee — voices in no uncertain language its regret at the “truly pitiable outcome of the effort to establish a Geological Survey of Colorado.” In a lengthy and well-written editorial, criticism is made of the proposed advisory board, particularly of the placing thereon of the presidents of the State University and the State Agricultural College; also, having the survey located at Boulder instead of Denver; of the naming as state geologist, the professor of geology of the State University, who may be a good teacher, but who, like the majority, may or may not be an effective executive; and lastly, of the paltry appropriation of $5,000 annually for this important work in a state productive of $50,000,000 and more yearly.

Exception is also taken to the naming of state institution teachers as assistants to the State Geologist, who ought to have the assistance of men less academic and having a knowledge of the exploitation of ore deposits and of the search for them.

This editorial expression, coming from a former Coloradoan, is worthy of consideration. It is in accord, in large part, with our own views, as our readers know. In addition to the criticisms made by our contemporary, we would like to emphasize another objectionable feature in this favorably reported bill, viz., the naming of any one as state geologist who is not to devote his entire time to the survey work. — from the Mining Reporter, vol. LV, March 28, 1907, no. 13, Denver, Colorado.

We’re happy to say that our current efforts to provide professional geologic information to the residents of Colorado far exceed the original scope of responsibilities and possibilities of the Territorial Geologist. But like those old-time miners, walking the mountains of this beautiful state, we also share a real passion for what we are doing.

You can find an in-depth history of the Survey and its 1872-legislated precursor, the office of Territorial Geologist, in IS-27 History of The Colorado Geological Survey (1872-1988), a free PDF download at our bookstore.


Citation: Rold, J. W., and S. D. Schwochow. IS-27 History of The Colorado Geological Survey (1872-1988). Information Series, IS-27. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1989.