IDM Mining Intersects 149.2 g/t Au and 59.9 g/t Ag High-Grade Intercept over 4.9 meters at Marc Zone, Red Mountain Project; 1.61 g/t Au over 106.5 meters at Lower AV (Smit) Zone

VANCOUVER, BRITISH COLUMBIA--(Marketwired - Sept. 5, 2017) - IDM Mining Ltd. (TSX VENTURE:IDM)(OTCQB:IDMMF) ("IDM" or the "Company") is pleased to announce continued drilling success at the Red Mountain Gold Project ("Red Mountain" or the "Project"), located 15 km east of Stewart, BC. The Company received assays for an additional 28 underground core holes from the Marc and AV Zones. These results are from the ongoing 23,000+ meter surface and underground resource expansion, infill and exploration drilling program.

Rob McLeod, IDM's President and CEO, commented: "We are highly encouraged to report the results of the ongoing 2017 drilling program. These results include 1,400 g/t Au over 0.5 meters: the highest grade core assay ever received at Red Mountain, and down-dip step-outs intersecting wide intervals of disseminated gold mineralization, with high-grade, tabular lenses within the newly identified Smit Zone. These results continue to demonstrate the expansion potential and the dynamic, robust nature of gold mineralization at Red Mountain."

Marc Zone

• Hole U17-1289 intersecting 1,400 g/t Au and 437 g/t Ag over 0.5 meters, within an interval of 149.24 g/t Au and 59.88 g/t Ag over 4.88 meters;
• Hole U17-1296 intersecting 26.61 g/t Au and 88.19 g/t Ag over 6.89 meters;

Holes U17-1289 and 1296 were drilled from the same setup targeting the Marc Zone and spaced 15 meters apart along strike. Both holes were drilled with the objective of refining near-surface mineralization. In this area, the Marc Zone is offset by a small strike-slip fault into separate blocks. U17-1289 includes the highest gold assay ever received at Red Mountain: 1,400 g/t Au and 437 g/t Ag over 0.5 meters. Capping the raw assay intervals to 55 g/t Au and 220 g/t Ag, holes U17-1289 and U17-1296 intersected 11.44 g/t Au and 37.64 g/t Ag over 4.88 meters and 24.16 g/t Au and 76.00 g/t Ag over 6.89 meters, respectively. These intervals are estimated to be approximate true width of the Marc Zone.

AV Zone and Identification of the Smit Zone

Underground drilling at the AV Zone targeted two key areas: 1) 25 meter systematic step-outs down-dip from current reserves, and 2) larger step-outs up to 300 meters down-dip from current reserves. The latter area suggests that the AV Zone transitions in to a wide area of disseminated gold mineralization, with higher-grade tabular structures within. The wide area, which can be traced in recent and historical drill holes for at least 200 meters along strike, is open down-dip and at depth, and to the north. This area has been named the Smit Zone in honor of former Red Mountain Project Manager for Lac Minerals, Hans Smit, and his son Peter Smit, who is employed by IDM as a junior mining engineer.

High-grade intercepts in step-out holes located down-dip from current reserves include: U17-1281 which intersected 11.54 g/t Au true width over 4.04 meters, and U17-1290 which intersected 11.58 g/t Au over 3.25 meters true width (10.84 g/t Au capped).

Significant intervals of wide disseminated gold mineralization in the Smit Zone were intersected in underground drill holes, ranging from 150 to 300 meters down-dip from current reserves within the AV and JW Zones. Highlights include:

• U17-1267: 3.14 g/t Au over 40.0 meters, including 5.48 g/t Au over 10.0 meters
• U17-1275: 1.46 g/t Au over 41.5 meters, including 4.23 g/t Au over 3.8 meters
• U17-1277: 1.88 g/t Au over 66.0 meters, including 6.81 g/t Au over 3.0 meters
• U17-1285: 2.19 g/t Au over 48.5 meters, including 6.66 g/t Au over 4.0 meters
• U17-1286 1.16 g/t Au over 120.0 meters including 10.14 g/t Au over 2.0 meters
• U17-1287 1.61 g/t Au over 106.5 meters including 4.98 g/t Au over 14.6 meters

Multiple drill holes ended in mineralization at their planned depth, including: U17-1277, 1278, 1285, 1286 and 1287 with additional assays pending for hole U17-1277 further uphole of the composited interval. These intercepts span approximately 125 meters of strike length, with both the higher-grade intervals and the wide disseminated zone dipping gently to the west. Mineralization continues to be open to the west and north, with U17-1267, which intersected 3.14 g/t Au over 40 meters, representing the northernmost drill hole in this area. The current AV zone reserves, coupled with recent and historic drill intercepts, suggests a gently dipping mineralized zone in excess of 500 meters in down-dip length, transitioning into the Smit Zone.

The major mineralized zones at Red Mountain are separated by wide spaced faults; the mineralization style and grade of these intervals are similar to the 141 Zone, which hosts reserves and resources, and is located approximately 250 meters to the west of the Marc Zone. This similarity suggests the major mineralized zones that have been encountered through drilling from the underground workings, may have been tabular and contiguous during the gold mineralizing event. This interpretation suggests further significant expansion potential to the north and northwest of current reserves and resources. Areas of gold mineralization within these results locally contain broad zones of elevated copper mineralization, along with anomalous bismuth and tellurium which is typical for the Red Mountain/Lost Valley system.

Assays are currently pending for six surface drill holes recently completed near the surface outcropping of the 141 Zone.

Complete drill results are as follows:

Drill hole collar information and location maps, core photos along with plan views, cross-sections and longitudinal sections can be viewed at www.idmmining.com.

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 recently 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 dor?(C) 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 Company recently submitted its Project Application and Environmental Impact Statement to regulators and stakeholders.

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 mineralized zones have been folded, and are often separated by dip-slip fault zones. Mineralization can vary in orientation from shallow to steeply dipping and are generally tabular. The Marc, AV and JW Zones range in widths from one to forty meters, averaging about sixteen 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

Samples for the 2017 exploration program are cut in-half with a diamond saw, with one-half placed in sealed bags and shipped to ALS Labs Ltd. in Terrace, BC for sample preparation, with pulps subsequently shipped to Vancouver, BC for gold and multi-element ICP analysis. A Quality Control/Quality Assurance program, including the insertion of Standards and Blanks, has been implemented. The 2017 exploration program at Red Mountain is performed under the supervision of Rob McLeod, P.Geo, President and CEO of IDM Mining Ltd. and a 'Qualified Person' under NI 43-101. Mr. McLeod 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, with a primary focus on the high grade underground Red Mountain gold project.

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. 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.