Antimony and Gold Recovery Process Design Is Largely Complete.

The following text, extracted from section 16.2 of the NI-43-101 June report, makes clear that yes, Silverado probably needs to process/study the currently planned 1000 ton bulk sample, but what was already completed by Bundtzen, Hazen, Silverado and Sepro SystemsTM using a 414 lb bulk sample, clearly shows that the metallurgical testing proves the antimony and gold can be easily separated. In addition, Sepro has already developed the Process Flow Diagram (PFD) and equipment specifications sufficient to begin detail engineering of the process and procurement of the equipment, when desired.

{My experience is that detail engineering would take just a couple months for a process as simple as this one. Initial procurement activities also could be completed in a few weeks (exclusive of fab. and delivery time) of course. My guess is that the rod mill and crushers may have the longest lead time, and I’ll look into that when I get a chance.}

From the Report, Section 16.2, page 75 (emphasis mine):

Quote: “Until very recently, Silverado has not completed mineral processing or testing of lode mineralization in the Nolan Creek area. Silverado has acquired a permit from the USBLM to collect and process a maximum 1,000 cu yd of material from the Workman’s Bench lode for metallurgical testing. This large bulk sample will be collected to determine further grinding, flotation, and other processing and mineralogical characteristics of stibnite.

In April 2008, the QP collected a 414 lb bulk sample of semi-massive to massive stibnite, vein quartz, and wall rock gangue all from the defined mineralized ‘A’ Zone in the Workman’s Bench underground workings (see Bundtzen (2008c).

The purpose was to determine the mineralogical nature of the antimony mineralization and the source of significant gold values. There is much variation in gold content of the stibnite zones even within constrained sample collection areas. The bulk sample was sent to Hazen Research Labs Inc. (Hazen) in Golden, Colorado, USA in order to discover the most optimal grind for potential marketing of a stibnite product, identify the mineralogical nature of gold and antimony values. Two reports were produced by Hazen in September:

1) Report #1-Flotation and Gravity Results, Workman’s Bench Stibnite-Gold Deposit, Wiseman District, Alaska; and 2) Report #2-Mineralogical Examination, Workman’s Bench Stibnite-Gold Deposit, Wiseman District (Hazen Research, 2008 a, b).

Both yielded a wealth of information. Hazen tested both gravity and flotation separation technologies, provided for heavy mineral components of the ore, predicted recovery of both stibnite and free gold, and suggested recovery technologies to be used in a future operation. The Hazen tests also provided Silverado with technical data used by Sepro SystemsTM to provide a preliminary design of a mill flow sheet featured in Figure 18.10 and discussed in Chapter 18.3 (Processing; pages 118-123).

Importantly, the bulk sample demonstrated that stibnite can be effectively separated from the other heavy mineral components such as gold and arsenopyrite, which report separately in the rougher concentrate table testing (see Figure 16.1). Hence the two economic products of the proposed mineral development, stibnite (antimony) and native gold, can be successfully separated.

The stibnite concentrates can be upgraded to market quality and most of the gold (90 percent according to Hazen test results) can be recovered at mine site.” End quote.

I urge everyone to study the Process Flowsheet in Figure 18.10 and process description in the report.

The process is simple and effective and performs high recovery (90%+).

Next Up: Trace element considerations, showing that claims by many that Silverado Nolan antimony and gold are polluted with arsenic and other impurities, are patently false.