North Bay Resources Inc (NBRI)

[mick]

#38/\08-26-2019/ Technical Assessment Report on the Mount Washington Property
http://www.northbayresources.com/2019_MW_43101.pdf

Vancouver Island, British Columbia
NTS 092F/14
BCGS 092F074 & 092F075
Latitude 490 45’ 23” Longitude 1250 15’ 22”
UTM NAD83 Zone 10N 337500E 5514000N
For
North Bay Resources Inc.
PO Box 162
Skippack, PA, USA 19474
By
Jacques Houle P.Eng.
6552 Peregrine Road
Nanaimo, B.C. V9V 1P8
August 26, 2019
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Mineral Processing and Metallurgical Testing
Metallurgical testing completed by previous operators on primary mineral occurrences in the
Mount Washington Property area has been included in the History section of this report. These
testing programs are listed by dates as follows:
• 1941 – by the Canada Department of Mines and Resources – Mines and Geology
Branch, for D.F. Kidd
• 1977-1981 – by B.C. Research for Imperial Oil Limited
• 1986 – by Bacon, Donaldson & Associates Ltd. for Freeport-McMoran Gold Co.
• 1988 – by Bacon, Donaldson & Associates Ltd. for Imperial Metals Corp.
• 1990 – by Bacon, Donaldson & Associates Ltd. for Biomet Technology Inc.
• 1988-1990 – by G.W. Hawthorne for Better Resources Ltd.
• 2004-2005 – by Knelson Research & Technology for Pearl Asian Mining
The initial 1941 metallurgical test work and ore microscopy by the federal government
identified the need to produce selective flotation to create multiple (3 or 4) concentrate
products from the Domineer mineralization to effectively recover gold, silver and copper. This
was probably considered too challenging for mine operators to develop at that time. Curiously,
any metallurgical test work for its copper-rich deposits by Mt. Washington Copper Co. is absent
in the public records. Although it is not known what if any metallurgical work was done by Mt.
Washington Copper before starting production in 1961, the fact that they tried to produce a
single (copper) flotation concentrate product suggests they were not concerned about
recoveries of precious metals. They acquired, relocated and erected the former Woodgreen
processing plant from the Motherlode Mine (MINFILE 082ESE034) near Greenwood, B.C. The
plant processed copper-gold-silver mineralization from 1956 to 1959 primarily from local
copper skarn deposits, in which all metals typically report to a single (copper) concentrate
product. This plant may not have been appropriate for processing the more complex gold-silver
rich Domineer mineralization, and not optimal for the copper rich Mt. Washington Copper
Deposits from the South and North Pits. In the 1977-81, B.C. Research on behalf of Imperial Oil
investigated copper heap leaching for processing mineralization at Mt. Washington, but
without positive results.

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As bio-leaching technology for processing complex ores began to evolve in the 1980’s, several
companies looked at Mt. Washington as a potential candidate site. Veerman-Botel Ltd.
investigated bio-leaching in the early 1980’s after acquiring the Mt. Washington property, as
did metallurgical consultants Bacon, Donaldson & Associates for several mining companies in
the late 1980’s. Better Resources solicited proposals from several metallurgical consultants and
engaged G.W. Hawthorne, P.Eng. in 1988 to design a processing plant to optimize primarily gold
recoveries from the Lakeview-Domineer Zone. By 1989, Mr. Hawthorne, supported by ore
microscopy work by J.F. Harris, used bio-oxidation technology to design a 200 TPD mine-site
plant producing two products: a copper-gold flotation concentrate and a gold bullion, with
combined recoveries of 92% gold and 68% copper. The plant would send 99% of the arsenic to
the tailings dam as ferric arsenate, but the recoveries and distribution of silver and other metals
in the ore are not mentioned.
In 2004, Pearl Asian Mining Industries Inc. engaged Knelson Research & Technology to conduct
gravity concentration test work for gold, silver and platinum from the Lake Zone of Wolf Lake
Property, with poor recoveries results. In 2005, mineralogical work on samples from the Lake
Zone by John Payne, Ph.D., P.Geol. of Vancouver Petrographics Ltd. for Pearl Asian Mining
provided detailed descriptions of gangue and sulphide minerals, and native gold which occurs
mainly with arsenopyrite. This is similar to the style of mineralization at Lakeview-Domineer.
In 2014, North Bay Resources Inc. engaged Blue Coast Research to complete specific gravity
tests and preliminary metallurgical testing of the MWC Tailings Dam. Four discrete samples
were collected from the tailings dam, with average composite grades of 0.15% copper, 0.13 g/t
gold, 3.43% iron and 1.03% sulphur. Solids specific gravity measurements from the four
samples averaged 2.71 t/m3, and in-situ specific gravity was estimated at 1.25 t/m3, based on
literature research by the author for comparable tailings dams. Flotation tests yielded copper
and gold recoveries of up to 60% and 67% respectively in concentrate, with grades of 1.4%
copper and 14% sulphur. The production of a salable final product is dependent on further test
work required to upgrade the rougher concentrate to produce at least a 20% Cu grade, which
based on preliminary results would be difficult to achieve at economic metal recoveries.

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