THE MINERAL INDUSTRY OF COLORADO 197 
 
was used in the company's research programs. 
 On April 6—7 the Fourth Symposium on Oil Shale was held in Denver.
Papers presented at the symposium were published by the Colorado ' School
of Mine's, one of the sponsoring organizations.11 
 In October the U.S. Department of the Interior and the AEC ordered negotiations
with industry for a joint nuclear test, called Project Bronco, aimed at eventual
in situ retorting of oil shale. Preliminary studies indicated the feasibility
of the proposed test, which called for detonation of a 50-kiloton nuclear
device in oil shale, followed by in situ combustion of the fractured shale
to extract the oil. Eighteen companies were to pay seven-eighths of the cost
of the experiment; total cost was estimated to be $6 million. 
 Peat.—The output of peat declined 15,123 tons, 41 percent below that
of 
1966. Peat was produced at 14 operations, one less than in 1966; all except
four had less production than in 1966. Boulder ' and Park Counties each had
three operations; Teller and Gilpin Counties, two; and Alamosa, Chaffee,
Lake, and La Plata Counties, one. Teller County had the largest production.

 Of the 21,988 tons of peat produced, 16,388 tons were used for general soil
improvement and 5,600 tons for mixed fertilizers and packing material. The
types of peat mined were moss, 45.1 percent; humus, 41.3 percent; and reed-sedge,
13.6 percent. Only 3,468 tons of the total output were processed. Except
for 726 tons that were packaged, the peat was bulk shipped; average price
per ton was $9.29. 
 Petroleum.—Petroleum continued to be the most valuable single mineral
commodity produced in Colorado, comprising 29 percent of the State's total
value. The downward trend characterizing production in the State since 1960
was reversed when 1967 output reached 33.9 million barrels, 413,000 barrels
more than in 1966. The small increase was more the result of improved recovery
techniques than of new discoveries. 
 Yielding 47 percent of the crude oil, the most productive oil reservoir
in the State was again the Rangely Weber pool. Although its cumulative production
at yearend reached 401.2 million barrels, output from the field declined
slightly (164,000 barrels) during 1967. 
 Arapahoe County joined the list of oilproducing counties with discovery
of the Black Jack field. Rio Blanco County, however, retained its first-place
rank with output from Rangely and Wilson Creek fields, followed in order
by Washington and Lo'gan Counties. 
 A total of 48 fluid-injection projects was underway in the State: 45 were
waterfloods, two were combined gas- and waterinjection, and one was gas-injection.
Four new projects, all waterfloods, were approved: Cache field, Ismay reservoir,
Montezuma County; Bobcat field, ~D" sandstone reservoir, Washington County;
Moccasin field, "J—l" sandstone reservoir,, Adams County; and Powder
Wash field,, Wasatch (A4H sandstone) reservoir, Moffat County. Of these,
only the Moccasinfield project was begun in 1967, ' on De-~ cember 2. The
Buckingham "D" sandstone waterflood, approved in 1966, was begun on March
5, 1967. Several injection programs were inoperative all or part of the year:
Aztec Wash, Azure, Bijou, Danforth Hills (Morrison reservoir), Keota, Liberty,
Luft, Phegley, and Winston. Total water injected in the projects was 134.8
million barrels (17,373 acre-feet). 
 API and AGA 12 estimated that the State reserves of crude oil at yearend
were 339.9 million barrels, a decline of 3.6 million barrels (1 percent).
Additions from revisions and extensions amounted to 26.5 million barrels;
new fields and pools added 3.3 million barrels. 
 Although total drilling was approximately the same as in 1966 exploratory
drilling increased by 15 wells (5.7 percent); development drilling, however,
declined. Success ratio of the wildcat drilling was 16.2 percent, an improvement
over the 12.2 percent of the previous year. Development drilling was 55.6
percent successful. 
 The Denver basin again accounted for 71 percent of the exploratory drilling;
the Colorado part of the Paradox basin was next with 19 wells in Montezuma
County, two in San Miguel, and one in La Plata. Sixty-nine percent of the
discoveries were in the Denver basin, also the site of 42: 
percent of the development drilling. Rio Blanco, however, was the leading
county 
 
 
 11 Fourth Symposium on Oil Shale Quarterly of the Colorado School of Mines.
V. 62, No. ~, July 1967, 173 pp. 
12 Reference cited in footnote 7, pp. 30-31.