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Soledad Mountain

The Soledad Mountain Project (the “Project”) is a gold-silver project located is located 5 miles south of the town of Mojave in Kern County, southern California. The Project uses conventional open pit mining methods and the cyanide heap leach and Merrill-Crowe processes to recover gold and silver from crushed, agglomerated ore.

Gold and silver production is projected to average approximately 74k oz and 781k oz respectively per year although this is expected to fluctuate from year to year depending upon the ore head grades. Gold and silver production is projected to be 807k oz of gold and 8.3MM oz of silver over a period of ~11 years. ✲

Access to site is from State Route 14 and an existing paved County road. A power line crosses the property boundary and the Union-Pacific railroad lines parallel State Route 14 within ~1 mile of the Project. The primary water supply for the Project is also located within a mile of site.

Highlights of the February 2015 feasibility study, calculated on 100% basis, include: ✲

  • Life-of-mine average annual gold production of 74k oz and silver production of 781k oz during full production Years 2-11;
  • First quartile total cash costs net of by-products of US$518/oz of gold (including royalties, California fees, property taxes, off-site refining charges and reclamation financial assurance) and of US$558/oz of gold including sustaining capital costs;
  • 11-yr mine life;
  • After-tax net present value of US$214MM (5% discount rate);**
  • After-tax internal rate of return of 28.3%;**
  • Utilization of a high-pressure grinding roll (the “HPGR”) to size and prepare ore particles for heap leaching (see below for benefits) and
  • Strong project economics with only 65% of the resource included in the feasibility study

*Base case gold price of US$1250/oz and silver price of US$17.00/oz

** Net of $25.4MM of capital expenditures spent prior to December 31, 2014

The primary ore types that will be mined are rhyolite porphyry and flow-banded rhyolite, pyroclastics and quartz latite porphyry representing approximately 70%, 10% and 20% of the ore tonnage respectively. Minor quantities of siliceous vein material (0.1%) will also be mined. The rock types will be found in different areas and at various stages of the mine life. The primary rock types are of extrusive volcanic origin and are quite similar in chemical composition and are high in silica with little or no clay.

The crushing-screening plant includes a primary and secondary crusher and screen in closed circuit with the secondary crusher. The HPGR is used as part of the crushing-screening circuit to prepare the ore particles for stacking on the two leach pads.

The HPGR consists of two counter-rotating rolls – one fixed roll and a ‘floating’ roll. The ‘floating’ roll is mounted on and can move freely on two slides and the grinding forces are applied by four hydraulic rams. Ore is choke-fed to the gap between the rolls.

Assessments carried out by two HPGR manufacturers, third party technical consultants, and Company management have indicated that benefits of using the HPGR could include:

  • Higher gold and silver recoveries due to the formation of micro-cracks in ore particles;
  • Faster gold and silver extraction rates;
  • Stronger agglomerates due to a more favorable overall particle size distribution and this will also impact the flow rate of solutions through the heap;
  • Lower capital costs than a four-stage, conventional crushing-screening plant;
  • Manageable dust control with fewer transfer points;
  • Lower energy consumption and thus lower operating costs and
  • Circuit flexibility that will readily permit future upgrades such as a finer HPGR feed size or the recycle of edge product

 This is forward-looking information and includes risks and assumptions. Click here to see our statement on forward-looking information. 

Aggregate Potential

Golden Queen Mining proposes an aggregate and construction materials business that will be developed once the heap leach operation is in full production, based on the location of the Project in southern California with close proximity to major highways and railway lines.

The California Department of Transportation projects aggregate demand of approximately 13 million tons per year for the area surrounding Palmdale, Lancaster, and Rosamond and less than 27% of this demand can be met from existing permitted resources. Similarly, estimates suggests that demand from the area surrounding Bakersfield is approximately 5 million tons per year for the next 50 years, and less than 46% of this demand can be met from existing permitted resources.

California updated its analysis of permitted aggregate reserves compared with 50-year projected aggregate demand in 2012. The analysis is available at:, and the accompanying map of aggregate supply and demand centers is available at:

Senate Bill 420 was affected in 2006 to recognize the need for local sources of aggregate in California. Senate Bill 420 requires the California Department of Transportation to use recycled aggregates in State paving projects where economical. In this instance, the waste rock from the Project would constitute a recycled waste product consistent with Senate Bill 420.

Aggregate Production from Waste Rock

Research suggests that up to 1 million tons of waste rock could be sold into the southern California aggregates market annually. The source of raw materials will be quality waste rock stockpiled on a level pad east of the East Pit. The waste rock can be classified into a range of products such as riprap, crushed stone, and sand with little further processing.

Every effort will be made to proceed with processing of the waste rock as early in the life of the mine as possible and it is expected that this can proceed shortly after the start of pre-production mining. Closing reclamation of the facilities required for the processing of waste rock, including the storage pad, will remain the Company’s responsibility.

An Economic Advantage

There are three key elements that should create advantages for the Company as an aggregate producer:

  • The run-of-mine waste rock and sand will be produced as a by-product from a mining operation. This should give the Project an economic advantage as an aggregate producer in comparison with producers that have to mine rock or obtain sand from alluvial deposits to produce aggregate.
  • Available infrastructure on site will have an important impact on the cost of producing aggregate and shipping aggregate or final products to market.
  • It has become difficult to obtain permits for new quarry developments in southern California. The Project has its permits in place and this should be a distinct advantage for an aggregate producer that wishes to work with the Company as a sub-contractor on site or as partner in a bulk concrete products facility on site.
  • It is important to note that no contributions from the sale of aggregate products will be included in the cash flow projections until long-term contracts for the sales of products are secured.
  • ✲ This is forward-looking information and includes risks and assumptions. Click here to see our statement on forward-looking information.

In the Community

Golden Queen is committed to the community of Mojave and is a longtime supporter of charitable, business and economic development activities in the region. The Company maintains memberships and involvement in multiple organizations including revitalization efforts focused on the town of Mojave.

In addition, the Company has invested over half a million dollars to date in the cleanup of the northern slopes of Soledad Mountain. An extraordinary amount of illegal dumping and remnants from historical mining operations have been removed from the area since 2006.

The Company is proud of its long history in California’s eastern Kern County and looks forward to benefiting the region’s economy for many more years to come.

This content is for documentation purposes only and does not express the opinions of the present day All rights reserved with original owner.
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