Midas Gold Update on Pilot-scale Metallurgical Testing for the Stibnite Gold Project, Idaho Successful metallurgical pilot plant runs identify opportunities to make the process flowsheet more robust, more economical, lower technical risk, and more environmentally sound
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NEWS RELEASE
February 21, 2018
#2018-02
Midas Gold Update on Pilot-scale Metallurgical Testing for the Stibnite Gold Project, Idaho
Successful metallurgical pilot plant runs identify opportunities to make the process flowsheet
more robust, more economical, lower technical risk, and more environmentally sound
VANCOUVER, BRITISH COLUMBIA – Midas Gold Corp. (TSX:MAX / OTCQX:MDRPF) today reported on
continuing progress in its feasibility-level metallurgical test program for the Stibnite Gold Project
(“Project”) located in Idaho, USA. This important component of the Project feasibility study ( “FS”) is
progressing well and is expected to be concluded in the second quarter of 2018. The work, conducted at
several laboratories, is being coordinated by Blue Coast Metallurgy Ltd. (“Blue Coast”) and M3 Engineering
and Technology Corp. (“M3”), under the guidance of a team of metallurgical experts working with Midas
Gold.
Highlights of the results of metallurgical testing since the completion of the 2014 preliminary feasibility
study (“PFS”), all of which should have economic benefits to the Project, include the following:
• A coarser primary grind, reducing energy and grinding media costs;
• Higher gold and antimony concentrate grades;
• Higher overall gold and antimony recoveries;
• Reduced reagent consumption, reducing operating costs; and
• Use of on -site limestone for pH control, significantly reducing the need for trucked -in lime,
thereby reducing operating costs . On -site limestone use also increases environmental
performance, improves downstream gold recovery and reduces reagent consumption, which
provides both environmental and economic benefits.
“Progress with metallurgical testing, including a number of pilot plant runs, has demonstrated potential
for improved environmental and economic parameters in the upcoming feasibility study,” said Stephen
Quin, President & CEO of Midas Gold Corp. “These test results represent another important milestone in
the advancement of the Stibnite Gold Project towards completion of a feasibility study.”
Previously Reported Progress
Earlier work, described in a press release dated February 14, 2017, achieved progress in risk reduction in
primary grinding design and in reducing projected costs of the flotation process while generally enhancing
metallurgical recoveries. Highlights of progress as compared to the PFS reported in that press release
included (see February 14, 2017 news release for details):
1. Reduced consumption of flotation reagents, reducing operating costs;
2. Coarsened primary grind (from 75 to 85 microns), reducing energy and grinding media costs; and
3. Improved antimony concentrate grades from 59% to 63 -65%, reducing shipping costs and
increasing payability.
This update provides information on key advancements made since the February 2017 press release.
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Reductions in Concentrate Production
The majority of capital costs associated with the processing plant for the Stibnite Gold Project are related
to the autoclave and associated processes, so a reduction in the tonnage of concentrate into this process
can be expected to reduce the size, and hence cost , of that part of the process facilities . Consequently,
recent flotation work has developed a cleaner flotation process that reduces the amount of material to
be processed through the proposed on-site pressure oxidation and related circuits, while still achieving
overall gold recoveries matching or exceeding those reported in the PFS. This work has included batch
and pilot plant programs, with the pilot plant performance closely replicating the enhanced metallurgy
achieved in batch testing.
Process Enhancements in Pressure Oxidation
During 2017, significant progress was made in the development of the pressure oxidation and
downstream unit processes for the Project, initially confirming work that had been done for the PFS, then
exploiting opportunities to make the process more robust and cost effective, and to reduce technical risk.
Initial tes ting, completed in mid -2017, provided the foundation for a successful, 6 -day pilot plant
campaign in Q4/2017 on flotation concentrate from representative composite samples of Yellow Pine and
Hangar Flats material. This program largely supported metallurgical recovery expectations from the PFS
and so validated the process as proposed in the PFS.
However, opportunities were identified during this work that have subsequently been shown to enhance
the process further. The key process refinement involved inco rporating the use of ground limestone in
the autoclave to control free acid levels, which offers some key benefits:
• It enhances the environmental stability of the final process products;
• By using limestone mined on-site as a neutralization medium, it substantially reduces the tonnage
of lime to be trucked to site, which would reduce operating costs and offsite vehicle traffic;
• It has been demonstrated in testing that the use of limestone improves the ease of downstream
processing and potentially reduces cyanide consumption, which would also reduce operating
costs; and
• It also makes the metallurgical performance more robust and less susceptible to variations in ore
types being mined from the various feed sources in the Project.
Further benefits are likely to be realized from this process enhancement. These are expected to have
further positive impacts on P roject economics, but at this stage these are not fully quantified. The
enhanced process, using ground limestone for pH control, has been extensively tested by both bench -
scale and pilot plant testing, and is a proven approach used effectively at other commercial pressure
oxidation operations. A variety of feed types from all three deposits have been tested and all were found
to respond well to the enhanced process.
Latest Gold Recovery Projections vs Pre-feasibility Study
Below, the overall recoveries of gold achieved from flowsheet development in the FS are compared with
those adopted for the PFS. Note that the final recoveries adopted for the FS may differ from those listed
below, depending on results from the variability studies currently underway:
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Low Antimony High Antimony
Yellow Pine Hangar Flats West End Yellow Pine Hangar Flats
Flotation recovery
FS testing to date
- Batch 93.7 91.9 n/a 91.4 91.8
- Pilot plant 92.3*
PFS projection 93.2 91.8 n/a 90.1 87.6
POX-CIL extraction
FS testing to date
- Batch 97.5 98.0 98.0 97.5 98.0
- Pilot plant 98.3*
PFS projection 97.6 97.0 98.2 97.6 97.0
Overall recoveries (Overall recoveries include assumed 0.8% post-CIL gold loss)
FS testing to date
- Batch 90.6 89.3 n/a 88.4 89.2
- Pilot plant 90.0
PFS projection 90.2 88.3 n/a 87.2 84.3
Notes:
* A blend comprising Yellow Pine and Hangar Flats materials was processed in the pilot plant.
n/a: West End projected recoveries by flotation/POX/CIP recoveries are variable and linked to sulphide content in the feed.
Overall recoveries are a blend of direct leaching and flotation/POX/leach and will be determined in the geo -metallurgical
exercise later in the study.
Work is presently focusing on fine-tuning the remaining downstream processes.
Geometallurgy and Variability
The geometallurgical program is advancing in parallel with the hydrometallurgical testing. A first phase,
involving diagnostic process testing of the different lithological and al teration ore types, has ( not
surprisingly) revealed links between ore geology and expected metallurgy. This work has been used to
create a suite of samples to be tested as part of the flotation variability program. These samples have
been selected to encompass the variability in plant feed types to be expected though the life of the
Project. This testing is currently underway and is expected to be complete within three months.
The pressure oxidation variability studies are largely complete, with one more round of tests planned,
mostly to provide samples for environmental testing of the combined (flotation and leach) process
tailings.
Details of the previous news releases, the Project and the 2014 Preliminary Feasibility Study can be found
filed under Midas Gold’s profile on SEDAR (www.sedar.com) or at www.midasgoldcorp.com.
Management Changes
At the end of February, 2018, Midas Gold’s Chief Operating Officer, Bob Barnes will be retiring from his
executive position. Nevertheless, Mr. Barnes will continue to serve on the Board of Directors of Midas
Gold Idaho, Inc. in a non-executive function, with continued emphasis on environmental compliance and
safety. During his six plus years with the Company, Bob has played a leadership role as the Stibnite Gold
Project has transitioned from exploration through PEA and PFS and has particularly left his mark on the
safety and environmental compliance aspects of site activities, where there was only one lost time
incident in five years of drilling and other site activities, and six years without a recordable environmental
incident.
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Also at the end of February, Rocky Chase, Midas Gold’s Vice President of Environment and Sustainability
will be departing the Company. During more than five years with the Company, Mr. Chase focused on
environmental compliance, baseline environmental data collection, permit application preparation and
many other tasks integral to the advancement of the Stibnite Gold Project into the regulatory process.
Midas Gold thanks both Mr. Barnes and Mr. Chase for their contributions to the Company over a number
of years and wishes them the best in their future.
For further information about Midas Gold Corp., please contact:
Liz Monger – Manager, Investor Relations
(t) 778.724.4704
(e): [email protected]
www.facebook.com/midasgoldidaho
@MidasIdaho
W www.midasgoldcorp.com
Compliance with National Instrument 43-101
The technical information in this news release has been prepared in accordance with Canadian regulatory
requirements set out in National Instrument 43-101 (“NI43-101”) and reviewed and approved by Stephen
P. Quin, P.Geo., President and CEO of Midas Gold Corp., and a Qualified Person. The metallurgical testing
program for the Stibnite Gold Project was carried out under the supervision of Christopher Martin,
MIMMM, C.Eng., a Qualified Person and Principal Metallurgist for Blue Coast Metallurgy Ltd.
About Midas Gold
M
idas Gold Corp., through its wholly owned subsidiaries Midas Gold Idaho, Inc., Idaho Gold Resources,
LLC and Stibnite Gold Company, is focused on the exploration and, if warranted, development of deposits
in the Stibnite
-Yel
low Pine district of central Idaho that comprise the Stibnite Gold Project. The principal
gold deposits identified to date within the Project are the Hangar Flats, West End and Yellow Pine deposits,
all of which are associated with important structural corridors, as
well as a mineral resource contained in
Historic Tailings.
Forward-Looking Information
Statements contained in this news release that are not historical facts are "forward-looking information"
or "forward -looking statements" (collectively, "Forward -Looking Information") within the meaning of
applicable Canadian securities legislation and the United States Private Securities Litigation Reform Act of
1995. Forward Looking Information includes, but is not limited to, disclosure regarding possible events,
conditions or financial performance that is based on assumptions about future economic conditions and
courses of action including actions taken with the goal of improving, expanding and de-risking previously
defined mineral resources; the timing and availability of future drill results; the potential for antimony
production from the Project; the anticipated completion of a feasibility study and filing of a NI 43 -101
technical report in conjunction therewith; potential sites for additional drilling that could result in
potential improved confidence, enhanced economic returns and/or extending higher grade areas. In
certain cases, Forward -Looking Information can be identified by the use of words and phrases such as
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“once”, “estimates”, “potential”, “opportunities”, “confirm”, “if” or variations of such words and phrases
or statements that certain actions, events or results "may", "could", “should”, "would", "might" "be
achieved". In preparing the Forward -Looking Information in this news release, Midas Gold Corp. (the
“Corporation”) has applied several material assumptions, including, but not limited to, that pending drill
results will be available in a timely manner without undue delay; that areas identified as po tential sites
for additional drilling will yield results consistent with management's expectations based on the 2014 PFS;
any additional financing needed will be available on reasonable terms; the exchange rates for the U.S. and
Canadian currencies will be consistent with the Corporation's expectations; that the current objectives
concerning the Stibnite Gold Project can be achieved and that its other corporate activities will proceed
as expected; that the current price and demand for gold will be sustained or will improve; that general
business and economic conditions will not change in a materially adverse manner and that all necessary
governmental approvals for the planned activities on the Stibnite Gold Project will be obtained in a timely
manner and on acceptable terms; the continuity of the price of gold and other metals, economic and
political conditions and operations. Forward -Looking Information involves known and unknown risks,
uncertainties and other factors which may cause the actual results, performance, or achievements of the
Corporation to be materially different from any future results, performance or achievements expressed
or implied by the Forward -Looking Information. Such risks and other factors include, among others, the
industry-wide risks and project -specific risks identified in the 2014 PFS and summarized above; risks
related to the availability of financing on commercially reasonable terms; operations and contractual
obligations; changes in exploration programs based upon results of exploration, including drill results;
changes in estimated mineral reserves or mineral resources; future prices of metals; availability of third
party contractors; availability of equipment; failure of equipment to operate as anticipated; accidents,
effects of weather and other natural phenomena and other risks associated with the mineral exploration
industry; environmental risks, including environmental matters under US federal and Idaho rules and
regulations; impact of environmental remediation requirements and the terms of existing and potential
consent decrees on the Corporation's planned exploration and development activities on the Stibnite Gold
Project; certainty of mineral title; community relations; delays in obtaining governmental approvals or
financing; fluctuations in mineral prices; the Corporation's dependence on one mineral project; the nature
of mineral exploration and mining and the uncertain commercial viability of certain mineral deposits; the
Corporation's lack of operating revenues; governmental regulations and the ability to obtain necessary
licenses and permits; risks related to mineral properties being subject to prior unregistered agreements,
transfers or claims and other defects in title; currency fluctuations; changes in environmental laws and
regulations and changes in the application of standards pursuant to existing laws and regulations which
may increase costs of doing business and restrict operations; risks related to dependence on key
personnel; and estimates used in financial state ments proving to be incorrect; as well as those factors
discussed in the Corporation's public disclosure record. Although the Corporation has attempted to
identify important factors that could affect the Corporation and may cause actual actions, events or
results to differ materially from those described in Forward -Looking Information, there may be other
factors that cause actions, events or results not to be as anticipated, estimated or intended. There can be
no assurance that Forward -Looking Information will prove to be accurate, as actual results and future
events could differ materially from those anticipated in such statements. Accordingly, readers should not
place undue reliance on Forward -Looking Information. Except as required by law, the Corporation does
not assume any obligation to release publicly any revisions to Forward-Looking Information contained in
this news release to reflect events or circumstances after the date hereof or to reflect the occurrence of
unanticipated events.