The Mineral Ridge gold deposits occur on the northeast flank of the Silver Peak range of the Silver Peak mining district. The mining district occurs along the Walker Lane structural corridor, a structurally complex region, with the Sierra Batholith to the west and the Basin and Range Province to the east. Within the corridor, Precambrian through Cenozoic age metamorphic, intrusive and sedimentary rocks occur that have been subjected to folding and thrust faulting, low angle extensional deformation, and high-angle faulting.

The precious metal deposits at Mineral Ridge consist of structurally controlled gold mineralization hosted by the lowermost unit of the Wyman Formation. The gold mineralization is invariably associated with quartz impregnations either as:
• Quartz veins and veinlets/stringers in alaskite
• Quartz veins and veinlets/stringers in Wyman Formation limestone
• Quartz veins ranging from about one foot to over 15 ft

Dilation resulting from multiple periods of dip-slip movement along a series of braided extensional faults created the conduits for the multi-stage emplacement of quartz and the attendant gold mineralization. In this sense, the Mineral Ridge deposits are considered to be detachment fault hosted.

The gold bearing quartz impregnations were emplaced along low-angle or bedding plane extensional faults developed in the limestone and alaskite rocks. There are two or more phases of quartz injection but it is apparent that only one phase is associated with the gold mineralization.

Gold is present as native gold and electrum that occurs as irregular shaped intergrowths in quartz associated with interstitial space and small fractures. Gold also occurs as irregularly shaped intergrowths and as fracture fillings associated with goethite, much of which was derived from original pyrite. In partially oxidized mineralization, gold occurs with both pyrite and goethite. Gold particle size varies from 1 to 2 microns to about 700 microns, but most of the particles are in the 5 to 50 micron size range, and should not lead to a significant particle nugget effect problem. Gold to silver ratios are typically in the 2:1 range. Because of the small gold particle size and intergrowths with quartz, extensive crushing is needed to allow for the effective cyanide heap leaching of the gold. Locally, minor amounts of galena, sphalerite and anglesite/cerrusite have been observed in the mineralization.

The gold mineralization at Mineral Ridge is primarily associated with milky quartz veins and lenses accompanied by local argillization and some sericitization. The individual zones can be as much as 50 ft thick, typically consisting of a higher grade quartz veins from five to 30 ft thick, surrounded by a lower grade envelope of mineralization. Two or more high grade zones are commonly observed stacked in en echelon patterns. Gold deposition is structurally controlled, and some of the highest grade mineralization is found in shoots that are at an oblique angle to the direction of movement of extension.

Gold is present as native gold and electrum that occurs as irregular shaped intergrowths in quartz associated with interstitial space and small fractures. Gold also occurs as irregularly shaped intergrowths and as fracture fillings associated with goethite, much of which was derived from original pyrite. In partially oxidized mineralization, gold occurs with both pyrite and goethite. Gold particle size varies from 1 to 2 microns to about 700 microns, but most of the particles are in the 5 to 50 micron size range, and should not lead to a significant particle nugget effect problem. Gold to silver ratios are typically in the 2:1 range. Because of the small gold particle size and intergrowths with quartz, extensive crushing is needed to allow for the effective cyanide heap leaching of the gold. Locally, minor amounts of galena, sphalerite and anglesite/cerrusite have been observed in the mineralization.

Gold deposits on the Mineral Ridge Property are hosted within a structural envelope in the lower unit of the Wyman Formation near its contact with the crystalline core rocks. Quartz and felsic intrusive boundaries are common in this structural zone. These boundaries are elongate within, and sub-parallel to the direction of extension as a whole and are exposed in outcrop and in the underground workings. Elongate, braided, ductile shear zones surround the boundaries, with these shear zones being preferentially in-filled by milky quartz veining associated with mineralization and the better gold grades. This zone of ductile shearing comprises the structural mineralized envelope, and is internal, and sub-parallel to the limits of the structural slab. Internal to the mineralized envelope, other, smaller-scale fault and fold sets occur, which correspond to higher grade mineralized shoots. Based on mapping of the historical underground stopes within the Mary and Drinkwater deposits, some of the high grade shoots historically exploited by underground methods were localized at the inflection point of small flexures where dilation zones were formed when the limb of the fold steepened. These shoots lie at an angle of 38° to 45° from the horizontal, versus the average 25° angle of the structural zone. It is believed that the highest-grade mineralized shoots are related to a second, perpendicular set of flexures accompanied by normal faulting that intersect the dilation zones.

The mineral deposits at the Project are being mined by conventional open pit mining methods. A mining contractor is being utilized to perform all mining functions including: blasthole drilling, blasting, loading and hauling, as well as road and pit maintenance functions.

The Mary pit is the largest of the pits with an overall strip ratio of 8.3:1 (waste:ore). Access to the Mary pit is via the existing ramp system. A new access is being developed by dumping waste material to the southeast of the final pit limits at a gradient of 10%. This new ramp will access the lower benches of the pit and is expected to be completed in the third quarter of 2014. With the exception of the last three benches accessed via a 40 ft single lane ramp, ramp widths are designed at 80 ft. The pit was designed to use 10 foot single bench with up to six benches mined before leaving a 22 ft catch bench. This corresponds to the mineral resource model block height. The benching system varies within the pit due to the access ramp and pit slope constraints. The final pit design utilizes a spiral ramp system to maintain a uniform ingress and egress for the pit. Mining in the Drinkwater pit will be completed in August of 2014. The remaining strip ratio in the Drinkwater pit is 1.9:1 (waste:ore). Access to this pit is via a haul ramp which utilizes switchbacks to maintain the road system on the south side or footwall of the Drinkwater pit. As the physical size of the two pits is relatively small, each pit is mined and scheduled as a single phase.

The satellite pits (Bluelite, Solberry, Brodie, and Wedge) are all relatively small pits. The satellite pits have an overall strip ratio of 7.4:1 (waste:ore). Access to the pits is developed using a spiral ramp system or a slot cut (Brodie pit) where appropriate. Access to each of the Satellite pits is via 50 foot single lane ramps with pullouts designed to allow the use of 100-ton haul trucks.

MRG processes ore at Mineral Ridge with multi-stage crushing (four stages) that produces an 80% minus 6 mesh material that is agglomerated with cement and stacked on a heap leach pad. The ore is leached at a solution application rate of 0.0025 to 0.0040 gpm/ ft² of heap surface. Solution passing through the stacked ore on the heap leach is discharged out the base of the pad via 10” perforated HDPE lines. These 10 inch lines discharge into the HDPE double lined pregnant pond which is then pumped into the ADR plant where the solution is contacted with activated carbon in a five cell vertical column Carbon-in-Column (CIC) system for recoveries of the precious metals contained. The solution exits the column reporting to a HDPE double lined barren pond. A pump system then pumps the solution back onto the heap leach pad for further leaching. The carbon is loaded to approximately 100 oz/ton gold and is removed from the column and sent to Kimberley, Idaho for custom stripping by Metals Research Corp. and then returned to site. The carbon can go through ten stripping cycles at Metals Research prior to being sent to Just Refining of Sparks, Nevada for smelting. Payment is received from this material based on loadings of gold and silver.

The existing crusher receives run-of-mine (ROM) material via a front-end loader which places the material in a 70 ton rock box which is conveyed to the 32” x 48” Svedala jaw via a vibrating grizzly feeder (VGF). Discharge from the primary crushing circuit (3-1/2” minus) is conveyed to the secondary crushing circuit consisting of a VGF, horizontal shaft impactor, and a feed/discharge transfer conveyor.

Discharge from the secondary crushing circuit (2-1/2” minus) is conveyed to a screen plant for segregation by size fraction. The screen plant consists of a three-deck vibrating screen and associated discharge transfer conveyors. Depending on the size fraction, screen plant discharge can be crushed further in the tertiary crushing circuit consisting of a cone crusher and several feed/discharge transfer conveyors, and the quaternary crushing circuit consisting of a vertical shaft impactor and several feed/discharge transfer conveyors.

Crushed material is conveyed across a belt weightometer and an automated multi-stage sample cutter is utilized to create a representative composite of the product. Cement is then added to the product stream via a cement silo and metering system which is conveyed to the agglomeration circuit which is located on the HDPE lined pad. Fresh water or barren solution is sprayed inside the balling drum (agglomerator) to bring the moisture content of the product to 8%. The agglomerated material is then grasshopper conveyed to the pad for radial stacking. The agglomerated material is cured for 24 hours before final placement on the heap.

Material placed on the existing heap leach pad by previous operators consisted of ore ranging in sizes from (ROM) to 80% passing 10 mesh. This material had been leached and was in various stages of recovery. Also, several areas of the existing pad had exposed sections of HDPE liner which required testing and inspection to be performed prior to being placed into service. All the exposed sections as well as sections that were excavated for testing met or exceeded state required standards. Prior to placing ore on the exposed liner sections of the pad, alternating 3” and 4” perforated drain lines were placed every 10’ to aid in draining applied solution.

Ore placed on the pad is being irrigated via buried drip tubes which allow for flow rates of 0.0025 gpm/ft.² on side slopes and 0.0040 gpm/ft2 on flat surfaces. Barren solution at an average pH of 10.5 and cyanide level of 0.2 grams/liter flows through the ore and is collected in the pregnant pond via 10 “ perforated lines located on the base liner of the pad. The pregnant leach solution (PLS) is pumped to the processing facility, where the gold and silver is removed from solution via Carbon-in-Column (CIC) recovery. The five cell vertical column is 23 ft. tall and has a diameter of 10 ft. Each cell is designed to contain a maximum of 5.3 dry tons of carbon for a total 26.4 tons of carbon. This vertical column is capable of an operating flow rate of up to 2,000 gpm when using 6 x 12 mesh carbon. This new column and the increase in process solution flow through the ADR plant will reduce the leach pads recoverable gold ounce inventory and improve gold solution recovery. The carbon is being shipped weekly to Metal’s Research in Kimberley, Idaho for custom stripping of the precious metals which will be captured in electro winning cells, retorted and melted into doré bars for shipment to Johnson Matthey’s in Salt Lake City for further refining. Stripped carbon returning from Metals Research is returned to MRG for reuse in the CIC circuit. As needed, the carbon will be acid washed to remove carbonate scaling and prolong its useful life. The typical life span of carbon being utilized at MRG is 10 cycles at which time the carbon will be sent off site for smelting and recovery of the contained precious metals.