IDM Mining Updates Progress on its Feasibility Study for the High Grade Red Mountain Underground Gold Project

VANCOUVER, BRITISH COLUMBIA--(Marketwired - Dec. 13, 2016) - IDM Mining Ltd. (TSX VENTURE:IDM) ("IDM" or the "Company") is pleased to announce an update on Feasibility Study ("FS") work for its Red Mountain Gold Project ("Red Mountain" or the "Project"), located 15 km northeast of Stewart, BC. IDM is targeting a spring 2017 release for the Feasibility Study.

IDM has engaged JDS Energy and Mining ("JDS") as Project Lead for the FS, with support from several independent engineering and consulting firms. In addition to Project oversight, JDS will handle underground mine design, metallurgy and project economics. Allnorth Consultants Ltd. has been contracted for site infrastructure planning and design. Access road design and engineering is being completed by Onsite Engineering Ltd. SRK Consulting is managing hydrology, geochemistry and underground geotechnical work. Knight Piésold Consulting is leading the design of the Tailings Management Facility ("TMF") and water management systems. An updated Resource Estimate will be authored by Dr. Gilles Arseneau, P.Geo and Andrew Hamilton, P.Geo with input from the IDM technical team.

"We are pleased to work with JDS on the Red Mountain Feasibility Study. Their recent experience in authoring a number of successful feasibility studies for mines in Canada and internationally, the construction and commissioning of the Silvertip Mine in northwest BC in less than one year and their expertise in cost control and innovative design for mine development in challenging northern environments makes JDS an ideal partner for the Red Mountain Project," said Robert McLeod, President and CEO of IDM Mining. "Incorporation of the 2016 drilling results, coupled with potential engineering improvements, may further enhance Red Mountain's robust economics."

"The entire feasibility study team selected for Red Mountain is comprised of key professionals and firms with recent, in-depth experience in northwestern BC," said Michael McPhie, Executive Chairman of IDM. "This team is working closely with our environmental assessment and permitting team, in transparent and mutually respectful consultation with Nisga'a Nation, to design a project that is both economically attractive and incorporates our commitments to environmental protection and stewardship as well as maximizing the benefits of the Project for local and regional communities."

Outcomes of the 2016 Field Season and Study Work Underway

1. Metallurgy

During the 2016 field season, infill and metallurgical drill holes were distributed throughout the three primary resource zones at Red Mountain: the Marc, AV and JW Zones. Test work and analysis is currently underway at Base Metallurgical Laboratories Ltd. This work includes variability sample selection followed by comminution, minerology, gravity and flotation testing. The program commenced with variability samples before creation of a global composite for each zone, allowing for characterization of each area to identify any anomalies in the sample results. The current proposed flow sheet suggests a flotation and leach gold recovery process, producing gold-silver doré bars.

2. Resources

Underground drilling during 2016 included infill drilling and primarily targeted the AV and JW zones, with the objective of potentially upgrading Inferred Resources to Measured and Indicated classification. Additionally, 25 meter spaced step-out underground and surface drill holes were completed at all of the major zones, the minimum spacing required for Indicated Resource classification at the Red Mountain deposit. Geology and resource modeling is currently underway, with an updated Resource Estimate planned for January 2017. Underground stope design by JDS will commence upon completion of the updated Resource.

3. Tailings Management and Design

Design work for the TMF is underway. An extensive site investigation program of drilling, mapping and lab testing was performed at the proposed Bromley Humps tailings site during 2016. Design work will be completed to environmental assessment ("EA") and relevant BC Mines Act standards, which can be more detailed than feasibility-level design. IDM has been working closely with regulators, Nisga'a Nation, on the TMF design and assessment of alternatives, including incorporating Best Available Technology (BAT) into all aspects of the Project.

4. Underground Geotechnical and Hydrogeology

SRK Consulting gathered extensive surface, underground and drill core geotechnical data during 2016, supplemented by historical work at Red Mountain. Ground conditions at Red Mountain are excellent: minimal ground support was previously required during the construction of the five by five meter decline in the early 1990s, and minimal work was needed by IDM during the 2016 underground rehabilitation work. SRK is also modeling groundwater hydrology and chemistry. Significant but manageable melt water inflows were encountered during the 2016 summer months in the underground workings, and a water management plan will be included in the FS.

5. Potential Project Improvements

The Red Mountain FS will build on the July 2016 NI 43-101 Preliminary Economic Assessment ("PEA"). The PEA identified multiple potential opportunities for the Project, including: reduction of capital costs through the purchase of used mining and processing equipment, expanding the resource base and the life of the mine and sharing capital costs, where possible. These opportunities will continue to be explored through the FS phase and appropriate cost savings will be identified, where possible.

About Red Mountain

The 17,125 hectare Red Mountain Gold Project is located in northwestern BC, 15 km northeast of the town of Stewart. IDM is advancing a Feasibility Study for a high-grade, underground gold mine, which envisions primarily bulk underground mining methods and the production of gold doré on site. The Project is advancing through the provincial and federal environmental assessment processes, with comprehensive, thorough, and ongoing consultation with Nisga'a Nation.

On April 4, 2016, the Company announced an updated mineral resource estimate reported at 3.0 g/t Au cut-off for the Red Mountain Gold Project.

Classification	Tonnage	Au (g/t)	Ag (g/t)	Oz Au	Oz Ag
Measured	847,200	9.38	34	255,400	920,700
Indicated	794,600	7.29	18	186,100	459,100
Measured + Indicated	1,641,800	8.36	26	441,500	1,379,800
Inferred	548,100	6.10	9	107,500	153,700

Red Mountain is a porphyry-related hydrothermal gold system, located in the Stikine terrain. Gold mineralization is associated with, and partially hosted within an early to mid-Jurassic multi-phase intrusive complex, with associated volcanic and volcaniclastic rocks and sediments. Many gold mineralized zones occur on the property, including five mineralized zones with established resource estimates. The five mineralized zones (Marc, AV, JW, 141 and 132) have been folded, and are often separated by dip-slip fault zones. The mineralized zones vary in orientation from shallow to steeply dipping and are generally tabular. The Marc, AV and JW Zones vary in widths from one to forty meters, averaging about fifteen meters in thickness. Gold and silver mineralization is associated with stockworks, disseminations and patches of coarse grained pyrite, surrounded by a pyrrhotite/sphalerite halo. Alteration facies includes strong quartz-sericite alteration.

Additional information, including the Company's NI 43-101 Technical Reports for the Red Mountain gold project, is available at www.idmmining.com and at www.sedar.com.

QA/QC AND QUALIFIED PERSON

Oversight of the Feasibility Study is performed by Wayne Corso, P. E. a consultant to IDM and 'Qualified Person' under NI 43-101. Rob McLeod, P. Geo, President and CEO of IDM Mining Ltd. has reviewed and approved the technical content of this release.

ABOUT IDM MINING LTD.

IDM Mining Ltd. is a mineral exploration and development company based in Vancouver, BC, Canada. The Company's current exploration and development activities are focused on precious metals in British Columbia and Yukon, with a primary focus on the high-grade, underground Red Mountain Gold Project, which is advancing through the BC and Canadian environmental assessment processes.

ON BEHALF OF THE BOARD of IDM Mining Ltd.

- Robert McLeod, President, CEO and Director

"Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release."

Forward-Looking Statements: Some statements in this news release contain forward-looking information or forward-looking statements for the purposes of applicable securities laws. These statements include, among others, statements with respect to the proposed exploration and development activities and their timing, resource estimates and potential mineralization, the anticipated timing for completion of an updated resource estimate and feasibility study. These statements address future events and conditions and, as such, involve known and unknown risks, uncertainties and other factors, which may cause the actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the statements. Such factors include, among others and in addition to those described elsewhere in this release, timing and success of future exploration and development activities, exploration and development risks, delays in obtaining or inability to obtain required government or other regulatory approvals, permits or financing, the risk of unexpected variations in mineral resources, grade or recovery rates, of failure of plant, equipment or processes to operate as anticipated, of accidents, labor disputes, and unanticipated delays in completing other development activities, the risk that estimated costs will be higher than anticipated and the risk that the proposed mine plan and recoveries will not be achieved, equipment breakdowns and bad weather, the timing and success of future exploration and development activities, exploration and development risks, mineral resources are not as estimated, title matters, third party consents, operating hazards, metal prices, political and economic factors, competitive factors and general economic conditions. In making the forward-looking statements, the Company has applied several material assumptions including, but not limited to, the assumptions that: required regulatory approval, permits and financing will be obtained; the proposed exploration and development will proceed as planned; with respect to mineral resource estimates, the key assumptions and parameters on which such estimates are based; that the proposed mine plan and recoveries will be achieved, that capital costs and sustaining costs will be as estimated, and that no unforeseen accident, fire, ground instability, flooding, labor disruption, equipment failure, metallurgical, environmental or other events that could delay or increase the cost of development will occur, and market fundamentals will result in sustained metals and minerals prices. The Company expressly disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise except as otherwise required by applicable securities legislation.