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tion, Mineral Exploration (Union Oil et al) and Utah International (See Plate One). These deposits are believed to contain adequate reserves/resources to eventually support integrated mine-mill complexes. Other uranium reserves/resources are controlled by Atlantic Richfield, Silver Bell Industries, Nedco-Teton, Conoco, Union Carbide, Wold Minerals, Texas Gulf and Rocky Mountain Energy Corporation (Union Pacific et al).

Additional exploration will, without doubt, expand the known uranium reserves/resources in the Red Desert area through new discoveries and extensions of known deposits. It is the writer's opinion that the Red Desert-Crooks Gap Area will ultimitely compare favorably with and probably surpass the uranium production from any of the other major districts in Wyoming.

Character of Mineralization

As is the case with most sandstone deposits in the Western United States, uranium in the Red Desert generally occurs as simple to complex 'roll fronts' ('C' shaped in profile). These deposits are epigenetic in the sense that they were formed subsequent to the deposition of the host sands. They occur at the interface of a geochemical cell between what is commonly called 'altered' and 'fresh' ground. This interface develops as the result of an envelope of advancing, oxidixingmineralizing solutions within the permeable host rock. These solutions 'alter' or change the character and appearance of the sandstone within



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the cell, through destruction of included pyrite, carbonaceous material and dark minerals. As previously mentioned, the most noticeable change is that of color - from typically gray to tan, buff, brown, greenish-gray and red.

The uranium in the mineralizing solutions may have been derived from leaching of volcanic tuffaceous rocks at surface; from leaching of arkosic sediments within the 'altered' portion of the host rock; or, more likely, from leaching of the Granite Mountains proper, which are anomalous in uranium content. Mineral deposits develop at the interface of the cell as the result of reduction of the oxidizing solutions causing precipitation of the dissolved uranium. The presence and amount of carbonaceous material and pyrite appear to be the major controlling factors for this precipitation. Thinning of the sandstones and diminishing grain size probably slow the advance of the oxidizing-mineralizing solutions and further enhance precipitation of the uranium.

Rackley (1974) notes that statistically, ore bodies most commonly occur where shales (clays) make up 20 to 50% of the host section and he further states that ore bodies most often occur where sandstones thin to less than 35 feet. An area that might fit the above model would be the broad belt, across the Red Desert, covering the fluvial-lacustrine facies area of the Green River sediments to the south and the Wasatch-Battle Spring sediments to the north. Entrapment of uranium



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might be expected to occur where fingers of arkosic sandstone intertongue with fine-grained clays and lignites. PCEC's West Red Desert Prospect covers much of this facies belt.

Previous Work on PCEC Property

The earliest exploratory work done on this prospect was carriedout by PCEC Prospectors with the aid of hand-carried and carborne scintillometers. Numerous radioactive anomalies were recorded and these, for the most part, were consistent with 'altered' outcrops of Eocene sandstones (See Plate Two).

As a follow-up to the surface prospecting, a drilling program was initiated in the Spring of 1970 on the S&L Claims. Thirtyfour holes (See Plate Four) were drilled in proximity to anomalous outcrops. This drilling was mostly shallow and oriented in a manner to penetrate sandstones down dip from 'altered' outcrops. Some drilling was apparently collared behind the outcrop; hence, it is of little use (Chico, 1971). Lithologic logs are available on only eight

of these holes.

The writer's interpretation of the gamma-ray logs disclosed the presence of radioactive intercepts in twelve holes ranging from trace to low-grade. The geometric character of these intercepts, together with 'altered' sands characterized by hematite staining, to depths of 400 plus feet, might be suggestive of a geochemical cell development.



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Some additional, shallow holes are probably warranted in the S & L

drill area.

99-374 O 78 17

A second drilling program was conducted on PCEC lands during

September and October, 1970. Sixty-nine holes were drilled for a total of 38,395 feet. These holes varied from 200 to 940 feet in depth

and averaged 556 feet. Spacing varied from less than one-half mile to more than one mile centers. Orientation of the profiles was generally east-west. This alignment is not the most desirable as it generally parallels the sedimentary and structural grain of the area and fails to show the changes in sedimentation that would be evident in profiles normal to the grain.

The ratio of clay-siltstone to sandstone in this drilling is fairly high; however, on the positive side, it is well demonstrated that sands occur over much of the PCEC property. These sands are mostly ten to twenty feet in thickness, although occasional sands reach 50 to 60 feet in thickness and apparently correlate over a distance of several miles (Campbell, 1970). Oxidation ('alteration' ?) was noted in lithologic descriptions from several holes at depths below 200 feet and trace mineralization - mostly related to sandstones was recorded in twenty-six holes. Further, microscopic sample studies indicate that these sands are arkosic; hence, a Granite Mountain source is probable. Grain size falls mostly into the fine- to medium- range (Chico, 1971).



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Previous Work on Properties available for Acquisition by PCEC


The writer did not receive any drilling of other data from who an they Silvertip Exploration's Cow, Pic, Pal, Mat and Rob Claim Groups

(See Plate One & Two).

Electric logs, location maps and sample descriptions were made available from two exploration programs previously conducted on the Silvertip claims located within the Union Pacific checkerboard area (See Plates One & Three).

The Getty Oil Venture covered most of Silvertip's checkerboard acreage and the extent of exploration was mostly limited to widespaced drilling. Thirty-one holes, varying in depth from 260 to 1,020 feet,were drilled in a 15-section area in the eastern portion of the claim block (See Plate Three). The maximum number of holes drilled per section was five on the Key Claims. Some sections received no drilling. Good sands were penetrated throughout the area and 'alteration' was reported by Getty in 19 holes. No significant mineralization was encountered on downhole radiometric surveys.

Getty drilled 28 additional holes, to depths of 420 to 1,100 feet, in the western portion of the claim block. The number of drill holes per section ranged from one to six on the Pat Group (See Plate Three). This drilling also penetrated good sandstone intervals throughout the 'Alteration' was reported by Getty in a least eleven of these holes and gamma ray logs recorded numerous anomalous radioactive kicks,


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