The uranium host rock sequence consists predominantly of a green to gray-green tuffaceous mudstone, which is interbedded with calcareous mudstone, carbonaceous mudstone, limestone, marl, lignite, chert and minor sand lenses. This sequence has been called the Anderson Mine Formation by Sherborne (1979) and ranges from 100 m to more than 500 m in thickness. This section has been tentatively correlated westward with the Chapin Wash Formation and most probably inter-tongues with the Chapin Wash Formation (Hertzke, 1997).

The Anderson Project mineralization is of syngenetic origin and similar in style to deposits found in Argentina and Lake Maitland Australia. Most or all of the lakebeds on the property facies exhibit some uranium mineralization. The highest grades and most continuous mineralization are
confined to the carbonaceous siltstones and lignitic materials. Occasional mineralization has also been noted in the basal sandstone of the lacustrine sediments and in the Lower Sandstone Conglomerate Unit. Carbonaceous material is known to interfinger with the basal sandstone, and carbon has been noted in the Lower Sandstone Conglomerate Unit. Remobilization of the uranium has resulted in the deposition of uranium as fracture fillings around and below the main mineralized zones (MinEx, 1978b).

Carbon tends to immediately fix uranium when it comes into contact with uranium in solution; therefore, much of the mineralization is restricted to the top or bottom of the carbonaceous facies. However, mineralization can occur in the middle of some carbonaceous zones; this relationship implies that mineralization occurred during the deposition of the carbonaceous material (MinEx, 1978b). Mineralization is also prevalent in calcareous facies.

Uranium mineralization in outcrops and the pit floor at the old Anderson mine was reported by the US Bureau of Mines in Salt Lake City as tyuyamunite (Ca(UO2)2(VO4)2·5-8H2O). Carnotite (K(UO2)2(VO4)2·3H2O) and a rarer silicate mineral, weeksite (K2(UO2)2(Si2O5)3·4H2O), was also reported in outcrop samples. Carnotite mineralization occurs as fine coatings and coarse fibrous fillings along fractures and bedding planes and has been noted in shallow drill holes and surface exposures.

The uranium mineralization found at depth on the former Urangesellschaft property was reported by Hazen Research, Inc. (Hazen Research) to be poorly crystallized, very fine grained, amorphous uranium with silica. This could be in the form of either coffinite (U(SiO4)1-x(OH)4x) or uraninite (UO2) in a primary or unoxidized state (Hertzke, 1997). Mineralogical studies performed by Hazen Research (1978a, 1978b, 1978c and 1979) on Urangesellschaft core found that mineralization was associated, for the most part, with organic-rich fractions of the samples. Specifically, the uraniferous material occurs as stringers, irregular masses and disseminations in carbonaceous veinlets with uranium up to 54% as measured by microprobe analysis. X-ray diffraction identified the mineral as coffinite. It is possible that an amorphous, ill-defined uranium silicate with a variable U:Si ratio is precipitated and, under favorable conditions, develops into an identifiable crystalline form (coffinite).

Of special note is the detection of high-grade, low-reflecting uraniferous material occurring with carbonaceous material in the siltstone. Similar assemblages in unoxidized mineralization have also been reported for the former MinEx property (Hertzke, 1997).

Urangesellschaft (1979a) distinguished seven mineralized zones, identified as Horizons A, B, C, D, E, F and G, with the youngest (uppermost) being Horizon A and the oldest (deepest) being Horizon G. The majority of uranium occurs in Horizons A, B and C within the property. A conglomeratic sandstone unit interbeds with these units, but does not contain uranium mineralization; it is referred to as the Barren Sandstone Unit and it lies between Horizon C and Horizon D. Consequently, Horizons A through C have been called the Upper Lakebed Sequence and Horizons D through G have been called the Lower Lakebed Sequence.

Grades of mineralization range from 0.025% U3O8 to normal highs of 0.3 to 0.5% U3O8 with intercepts on occasion of 1.0% to 2.0% U3O8. Secondary enrichment of the syngenetic mineralization is observed along faults and at outcrops (Hertzke, 1997).

The geologic and topographic setting of the Anderson Uranium Project is such that mineralization occurs at the surface in the north and reaches depths in excess of 1,800 to the south due the geologic dip and local terrain. As a result portions of the deposit are amenable to open pit mining methods while others are more suited to underground methods. The current conceptual design approach includes conventional mining via open pit, highwall mining, and underground mining.

OPEN PIT:

Open pit mining has two major facets, primary stripping or the removal of overburden and the mining of the mineralization as it is exposed by the stripping. Primary stripping would operate 2, 10 hour shifts per day on a continuous basis. Manning would consist of 3 rotating shifts with each operator working approximately 208 days per year or 2,080 hours. Mining would be accomplished on a single daylight shift operating 5, 10 hour days for approximately 260 days per year. If it were necessary to increase production, it is recommended that the mining remain a daylight operation for grade control purposes but the days and shifts be extended, i.e., 2 rotating crews working 4, 10 to 12 hour shifts on a continuous basis.

The pit would begin in the shallower areas to the north (lower stripping ratio) and proceed to the deeper portions of the pit to the south and west. Mining will be predominantly in the C zone although the pit will intercept some mineralization in the A and B zones. Open pit was sequenced into 9 open pits over a 10 year period. It was assumed that ¼ of the volume of the pit material would be rehandled to reclaim the pit and heap facilities. This sequence is conceptual and has not been optimized. A pit highwall sloped of 1:1 was used in the conceptual designs.

Highwall mining is applicable in situations where the open pit stripping ratio exceeds reasonable economic limits and there is access to mineralization continuing from an open pit highwall, trench cut, or outcrop. The conceptual pit design reaches a depth of 600 feet along the southern pit limits. Along the southern wall of the pit mineralization in the C zone is continuous and extends below the highwall. Highwall mining can begin in the east and central pit areas in year 4.

Highwall mining is an historic mining practiced with the most common method employing large augers. The highwall miner developed by Bucyrus (pictured below) has only been available since 2010. This equipment is gaining popularity in thin seam coal mining and conceptually would be applicable to the Anderson Project for mineralization which extends from the pit wall approximately 1,000 feet or less. The advantage over conventional underground mining is lower cost operation, lower capital costs, and higher recovery. For the base case 75% extraction was applied to the highwall mining areas.

Even with the extension of the open pit to its maximum limits, and application of highwall mining where possible, additional resources would only be accessible via underground mining. The conceptual mine plan incorporates a room and pillar mine operation with decline access from the open pit highwall. Underground mining would be exclusively in the C zone and could begin as early as year 6 following the completion of pit 4.

Based on the tenor of the mineralization, i.e. tabular, continuous, and reasonable in thickness, 6 to 10 feet within the conceptual mine area; the cost model includes CAPEX and OPEX for underground mine operations utilizing a continuous miner. For the base case 60% extraction was applied with no pillar recovery or retreat mining.

The planned uranium recovery method at the Anderson Project is conventional heap leaching which includes: the mobilization of uranium into solution from the mined material stacked on the heap pad via acid leaching, delivery of uranium rich solutions to a recovery plant (mill), and concentration of the uranium via Ion Exchange (IX).

Uranium recovery at the Anderson Project include the following processes:
• stacking of mined material on the heap leach pad;
• application of leach solution;
• collection of pregnant leach solution (PLS);
• filtering of sand and fines from PLS;
• IX to extract uranium from solution and load it on resin;
• Shipment of the loaded resin to EFR’s White Mesa Mill for stripping, precipitation, washing, drying, packaging, storage, and loading as yellowcake.

The uranium recovery or “milling” process equipment will be housed in a single building within the proposed mill boundary. Loaded resin will be produced on site. Yellowcake processing, including precipitation, washing, drying, packaging, storage, and loading, will be completed offsite. Reagent storage and distribution systems will be located within or next to the process buildings.

Processing (‘milling’) begins as run-of-mine product is crushed and then stacked on the double lined heap leach pad using covered belt conveyors and a covered radial arm stacking (RAS) belt . The stacked mined material is leveled with low ground pressure equipment forming a “lift”. A protective layer of gravel is place on top of the lift to mitigate fugitive dust and transport of radioparticulates from the heap. A drip irrigation system using conventional plastic piping is then installed on top of the completed lift, and the heap is ready for the application of leach solutions.

The general flow of solutions and uranium within the heap and recovery plant is as follows:
• The process begins with the pumping of the refortified leach solution from the Barren Pond to the top of the heap where it is applied using drip emitters.
• The leach solution consists of water; an oxidizing agent (sodium chlorate, to convert the uranium to the soluble hexavalent state), and a complexing agent (sulfuric acid) to complex and solubilize the uranium.
• The result of the heap leach process is a pregnant leach solution (PLS) containing a mixture of uranyltrisulfate (UTS) and uranyldisulfate (UDS). The process solution percolates through the stacked mined material via gravity drainage and is intercepted by the heap leach pad liner system and then gathered into collection pipes, which drain by gravity into the collection pond and is recirculated until the concentration meets the criteria for PLS.
• The PLS is then pumped from the collection pond into the IX plant where the PLS is filtered to remove suspended particulates, and the uranium is loaded on the resin.
• The resulting uranium-depleted solution, called barren leach solution, flows by gravity from the IX plant to the barren pond. This barren solution is refortified with additional acid and oxidant and additional make-up water. It is then pumped back to the heap in a continuous cycle.
• Resin is shipped from the plant to EFR’s White Mesa Mill for final processing to yellowcake.