Copper Flat is a porphyry copper- molybdenum deposit that is approximately 1,400 by 2,100 ft in plan view occurring within a small structurally controlled quartz monzonite stock that has intruded a circular block of andesite approximately 4 miles in diameter. The porphyry includes a variably mineralized west-northwest-trending hydrothermal “breccia pipe,” that lies immediately south of the Patten fault, that is about 1,400 ft long and 500 ft wide.

Sulfide mineralization is present as veinlets and disseminations in the quartz monzonite, but is most strongly developed in and adjacent to the west end of a steeply dipping breccia pipe, that is centrally located within the CFQM stock and elongated in the northwest-outheast direction roughly along, but south of the Patten fault. The sulfide mineralization first formed in narrow veinlets and as disseminations in the quartz monzonite with weakly developed sericitic alteration. This stage of mineralization was followed by the formation of the breccia pipe and the introduction of coarse “clotty” pyrite and chalcopyrite along with veinlet controlled molybdenite and milky quartz, and the development of strong potassic alteration. Typically, the total sulfide content ranges from 1 percent (by volume) in the eastern part of the breccia pipe and the surrounding CFQM to 5 percent in the CFQM to the south and west. Sulfide content is highly variable within the breccia, with portions in its western part reportedly containing as much as 20 percent sulfide minerals.

The breccia pipe, which can best be described as a crackle breccia, consists of rotated angular to subangular fragments of quartz monzonite varying from 1 inch to more than 18 inches in diameter. Previous workers have suggested that the breccia may have formed by autobrecciation resulting from retrograde boiling. Two types of breccia have been identified as distinguishable units based on the dominant mineral filling the matrix between clasts. Drilling has shown that the two breccia types, biotite breccia and feldspar breccia, grade into one another as well as with the CFQM. Interestingly from a recovery perspective, metallurgical testing has shown that the mineralization behaves virtually the same irrespective of the lithology.

Molybdenite occurs occasionally in quartz veins or as thin coatings on fractures. Minor sphalerite and galena are present in both carbonate and quartz veinlets in the CFQM stock. Preliminary evaluations of the mineralization at Copper Flat in 2011 indicate that copper mineralization concentrates and trends along the N50°W structural influences, whereas the molybdenum, gold and silver appear to favor a N10°-20°E trend.

The Copper Flat project is planned for production using conventional hard rock open pit mining methods. Ore production to the mill is planned at 29,600 tpd (10,800 ktons/yr) for the first 6 years followed by 27,125 tpd (9,900 ktons/yr) for the remaining mine life. The mine production schedule was developed with the goal of filling the mill at required ore rate and maximizing the project return on investment. The total material rate is tied to equipment productivity and amounts to 17,500 ktons/yr or 47,945 tpd for the first 5 years. The mine is scheduled to operate 365 days/yr with two, 12 hour shifts/day. Bench heights are currently planned to be 25 ft high. Drilling will be completed with three rotary blast hole rigs with 45,000 lb pull down capacity and 6.5 in diameter blast holes. The blasted rock will be loaded into 100 ton haul trucks using two 19 cu yd front end loaders.

The mine plan was developed with a phased approach. The floating cone algorithm was used as a guide to the design of the phases or pushbacks. Three phases were designed for the Copper Flat project with approximately 300 ft of operating width on each bench within a phase. Phase 1 was sized to contain roughly 1.5 years of ore. The phases were tabulated from the block model and those three tabulations were used as input to the development of the mine production schedule.

The mine production schedule was developed with the goal of feeding the mill at through put rates of 29,600 tpd (years 1-5) and 27,125 tpd (remaining LOM) and maximizing the project return on investment. Multiple mine production schedules were developed that analyzed alternative cutoff grade strategies versus mine total material movement.

The process selected for recovering the copper and molybdenum minerals is considered “conventional.” The sulfide ore is crushed and ground to a fine size and processed through mineral flotation circuits. The following items summarize the process operations required to extract copper and molybdenum from the Copper Flat sulfide ore.

Size reduction of the ore by a primary gyratory crusher to reduce the ore size from runof-mine (ROM) to minus 175 mm.

Stockpiling primary crushed ore and then reclaiming by feeders and conveyor belt.

Grinding ore in a semi-autogenous (SAG) mill primary grinding circuit and a ball mill secondary circuit prior to processing in a flotation circuit. The ball mill will operate in closed circuit with hydrocyclones to deliver an ore size of 80 percent passing 140 µ to the flotation circuit.

Gravity separation will be conducted on a bleed from the hydrocyclone underflow slurry to remove gravity recoverable gold ahead of fl ........