Milling Circuit (Maverick) I don`t have sufficient knowledge in this area, but I will give it high level shot - with regards to identifying hints as to whether the Maverick (Puffy Lake) mill can process more than just gold (if other medals eventually come along, either from Auriga`s property or nearby properties, either from 100% owned ore or through toll processing).
The Maverick ore body is strictly a gold mineralized body, with maybe a slight touch of silver and perhaps very minor traces of non-material base metals. However, the Sherridon, Flin Flon and Snow Lake mining areas are primiarily base medal or VMS areas - with some pure gold deposits in between (i.e. Maverick and New Britannia). If Auriga decides to generate extra revenues in the future via toll processing for other companies or decides to purchase deposits / extra ore from the nearby Sherridon, Flin Flon or Snow Lake areas then milling flexibility might be more accommodative to this strategy.
During the historical production period it looks like the Puffy Lake mill operated with a flotation circuit. This might be a clue about its processing flexibility. Also, it has a concentrator, which is suppose to be in excellent shape.
I think the flotation circuit and the concentrator could be helpful in processing / separating other medals, but I`m not 100% sure.
I have noticed other operations in the past where gold was recovered via a CIP (Carbon in Pulp) system (where the gold was liberated into a cyanide solution) and then the rest of the material subsequently went through a Gravity Circuit to recover the balance of the recoverable gold (to get to, say, a 90% overall recovery rate) - a two step process. I think the CIP system is used mainly when the ore is simple and pure (mainly gold).
For example, High River Gold performed an economic study (at Berezitovy) - prior to the 2008 market crash - to add 2 flotation circuits to process the mine tailings and recover zinc and lead and to increase the recovery of silver.
I know that Berezitovy had a CIP system. I don`t know if they had a Gravity Circuit as well (or if the recoveries were good enough with a CIP system only, that a Gravity Circuit was not required to recover further gold). Either way, High River needed to put in 2 Flotation Circuits (which I think is more advanced than a Gravity Circuit - I think the Flotation Circuit uses chemicals in the separation process, which is one difference versus the Gravity Circuit) in order to produce a zinc concentrate and a lead concentrate.
Of note, High River looked at putting in 2 Flotation Circuits. I don`t know enough about this subject matter to know if a separate circuit is required for each additional base metal.
Anyway, this is from pg. 47 of the latest Maverick PEA:
``13.1 H
ISTORIC PUFFY LAKE MILL OPERATION
The existing Puffy Lake mill was built in 1987 and operated from January 1988 to April 1989. The nameplate rating of the mill is 1000 t/d and rates of up to 1500 t/d for short periods has been reported, although average production was generally well below 1000 t/d.
The process consisted of conventional crushing and grinding to a target grind of 100 μ followed by flotation to produce a sulphide concentrate containing gold. A jig in the grinding circuit recovered coarse free gold.
The flotation concentrate was reground and leached in a conventional cyanidation plant using drum filtration for liquid/solid separation followed by Merrill-Crowe recovery of gold from solution. Precipitated gold was smelted to yield a doré gold product.
Flotation tailings and cyanide circuit filtration tailings were discharged directly to tailings. A barren solution bleed to tailings was required and was treated with hydrogen peroxide to destroy cyanide prior to discharge.``