IDM Mining Announces Resource Update at the Red Mountain Gold Project and Reports Significant Increase in Measured and Indicated Resources

VANCOUVER, June 19, 2018 /PRNewswire/ - IDM Mining Ltd. (TSXV: IDM) (OTCQB: IDMMF)("IDM" or the "Company") is pleased to announce the results of an updated mineral resource estimate for its 100%-owned Red Mountain Gold Project ("Red Mountain" or the "Project"), located in the Golden Triangle of northwestern British Columbia, near the town of Stewart, BC. The updated mineral resource estimate includes the results from additional drilling completed by IDM during 2017, primarily from the underground workings and incorporates a more robust geological model. The resource estimate is authored by Dr. Gilles Arseneau, P.Geo and Andrew Hamilton, P.Geo with input from IDM's technical team.

Highlights at a 3.0 g/t Au cut-off are as follows, with changes relative to the 2017 mineral resource estimate:

• 39.2% increase in measured gold ounces or 147,600 oz Au and measured tonnes increased by 581,900 or 46.7%, maintaining a high-grade of 8.92 g/t Au and 28.30 g/t Ag;
• 20.7% increase in measured and indicated ("M&I") gold ounces or 120,900 oz Au to 704,600 ounces of gold plus 2,026,800 ounces of silver at an average grade of 7.91 g/t Au and 22.75 g/t Ag;
• Measured and indicated tonnes increased by 33.6% or 696,600 tonnes to 2,771,300 tonnes;
• Inferred Resources of 61,400 ounces of gold averaging 6.04 g/t Au, a slight decrease in ounces of 5.2% primarily due to strong resource conversion;
• Vast majority of inferred resources in the Marc, AV and JW converted to M&I;
• Initial resources reported for Smit, SF, Bray, Chicka and Cambria Zones;
• This updated mineral resource estimate, along with improved geological interpretation and engineering optimization work will support an updated feasibility study expected to be completed in the autumn of 2018.

"Our 2017 underground drilling program successfully increased and upgraded high-grade, bulk-mineable resources at Red Mountain and demonstrated significant expansion potential with the addition of several new zones," said Robert McLeod, President and CEO of IDM Mining. "Coupled with the advanced stage of the EA and EIS review, along with the ongoing and thorough consultations with the Nisga'a Lisims Government, we believe that Red Mountain will be the next underground gold mine in BC."  

"The increase in tonnage and contained metal in the measured and indicated categories is a material addition to the deposit," said Ryan Weymark, VP Project Development.  "These additional resources will be included within an update to the 2017 Feasibility Study, which will also incorporate an optimized underground mine plan incorporating opportunities identified through the Value Engineering phase."   

Mineral Resource Estimate

The updated mineral resources for the Red Mountain Project are reported at a 3.0 g/t Au cut-off with an effective date of June 15, 2018.

The resource update incorporates information from previous drilling, plus results from 29,312 meters of drilling completed during 2017 (104 additional underground, eight surface and three geotechnical core holes), and local trenching/channel sampling.  Mineralization was primarily modelled at approximately 2.5 g/t gold grade based on the underground, bulk-mineable nature of the orebody, primarily amendable to long hole stoping for main mineralized areas including: Marc, AV, JW and peripheral zones, with consideration for sulphide mineralization (primarily pyrite, with local pyrrhotite and sphalerite) and alteration zonation (primarily sericite and silica).  Mineralized zones generally follow brecciated contacts between host intrusive (Hillside porphyry) with sediments and volcanic rocks.  The mineralized horizon folded by large amplitude (>150 meter) folds and separated into different blocks and zones by post-mineralization faults.  

The current mineral resource estimate, effective date June 15^th 2018, was prepared by Dr. Gilles Arseneau, P.Geo, and Andrew Hamilton, P.Geo, using 3D GEMS block modeling software.  Resources were estimated from 415 surface and underground core holes with 622 intercepts within 20 different solids into 4 x 4 x 4 meter blocks.  Interpolation was by ordinary kriging, or inverse-distance squared methods on smaller or dispersed data sets, with anisotropic search ellipsoids designed to fit the strike and dips of the zones.  An extensive quality control and quality assurance ("QA/QC") review was completed on all 2017 and previous exploration work and a comparative analysis was performed on drill hole data, underground bulk sampling and geology. Bulk density was interpolated using inverse-distance squared method where there was sufficient data populations.  For zones with sparse data, average values from the data available for a given zone were applied. Comprehensive metallurgical studies have indicated gold recoveries for the main resource zones (Marc, AV, JW, 141) range from 88.1% to 92.8% and average 90.9% (tonnage weighted). 

Mineral Resource Statement by zone for the Red Mountain Project at a 3.0 g/t Au cut-off Grade*

*Note: 3.0 g/t Au is used as the cut-off grade for underground mining. Due to typical large thicknesses, bulk mining methods, primarily longhole stoping are envisioned. Totals may not add due to rounding.

In the 2017 mineral resource estimate, grade estimates were based on capped 1.5 meter composited assay data.  Gold values were top cut to 55 g/t and silver values were top cut to 220 g/t.  For the updated 2018 mineral resource estimate, it was decided to cap raw assays with top cuts for gold and silver on a zone by zone basis, as per the following table, prior to compositing to 1.5 meters.

OK = ordinary kriging; ID2 = inverse distance squared

Sensitivity

The 2018 mineral resource estimate is reported at a 3.0 g/t Au cut-off grade. Cut-off grades may be re-evaluated considering prevailing market conditions (including gold prices, exchange rates and mining costs).  Opportunities identified during the Value Engineering phase show potential for reduced operating costs and the potential for lowering the cut-off, which will be validated through the proposed update to the 2017 Feasibility Study. For example, potentially lowering the cut-off to 2.5 g/t Au would add 301,000 additional M&I tonnes and 85,500 additional inferred tonnes.   

The reader is cautioned that the figures in this table are not a Mineral Resource Statement. The figures are only presented to show the sensitivity of the resource estimates to the selection of cut-off grade.

IDM acknowledges the team of geologists that executed the successful 2017 drilling program ahead of schedule, under budget and without a lost time incident, as well as completing the geological and resource modelling herein, specifically: Natalie King, Marilyne Lacasse, Andrew Hamilton, John Tejeda, Christopher Smith, Harley Hoiles, Wes Hodson and Robert McLeod.

Next Steps

During 2017, step-out holes on 25 meter spacings were completed on all of the major zones.  Geological interpretation subsequent to the completion of the drilling program noted that high amplitude folding deformed a brecciated intrusive/sediment contact zone (see IDM News Release February 13, 2018).  Future drilling will target expansion to gold mineralization along the brecciated horizon, in high-priority areas such as; between the Marc and 141 Zones, north and west of the Smit Zone and east of the SF Zone. Additionally, conversion of inferred resources would be targeted.

IDM intends to update the 2017 Feasibility Study incorporating the updated M&I resources into the mine plan, as well as the multiple potential operating and capital efficiencies that were identified during the Value Engineering phase (see IDM News Releases November 30, 2017 and March 20, 2018).

About IDM and Red Mountain

IDM Mining Ltd. is an exploration and development company based in Vancouver, BC, Canada focused on advancing the Red Mountain Gold Project towards production.  The 17,125 hectare Red Mountain Gold Project is located in northwestern BC, 15 km northeast of the mining town of Stewart.  In 2017, IDM announced the results of a Feasibility Study for a high-grade, underground gold mine, which includes 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.  The Project is currently in the formal review phase of the BC Environmental Assessment Office and the Canadian Environmental Assessment Agency. 

Technical Report

A technical report, which will include this resource estimate, will be posted on the Company's website at www.IDMmining.com and filed on SEDAR at www.sedar.com within 45 days.

IDM's updated resource estimate and a virtual tour of the Red Mountain Gold Project can be viewed at www.Vrify.com and Apple users can download from the App store.  Additional figures and tables can be viewed in an updated corporate presentation on IDM's website.

Dr. Gilles Arseneau, P.Geo, a 'Qualified Person' for the purpose of National Instrument 43-101 Standards of Disclosure for Mineral Projects of the Canadian securities administrators ("NI 43-101") has approved the disclosure of, and is the qualified person responsible for, the scientific and technical information in this news release inclusive of the resource estimate information. He has verified the data disclosed.

Rob McLeod, P. Geo, President and CEO of IDM Mining Ltd. and Ryan Weymark, P.Eng., Vice-President of Project Development have reviewed and approved the technical content of this release.  Both are 'Qualified Persons' under NI 43-101.

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 Company's plan to update its current 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.

SOURCE IDM Mining Ltd.