IDM Mining's Step-Out Drilling Intersects 6.23 meters True Width of 12.95 g/t Au and 48.83 g/t Ag at the Red Mountain Gold Project

VANCOUVER, BRITISH COLUMBIA--(Marketwired - May 23, 2017) - IDM Mining Ltd. (TSX VENTURE:IDM)(OTCQB:IDMMF) ("IDM" or the "Company") is pleased to announce assays from the initial six underground core holes for the 2017 season at the Red Mountain gold project ("Red Mountain" or the "Project"), located 15 km east of Stewart, BC. To-date, 23 underground drill holes have been completed as part of the ongoing 2017 underground drilling program.

Highlights from the recent underground infill and step-out drill results (capped) include:

• U17-1228: 1.82 meters true width at 19.25 g/t Au and 35.65 g/t Ag; AV Zone step-out
• U17-1229: 6.23 meters true width at 12.95 g/t Au and 48.83 g/t Ag; AV Zone step-out
• U17-1231: 5.00 meters true width at 8.78 g/t Au and 53.04 g/t Ag; AV Zone step-out
• U17-1233: 25.00 meters true width at 6.15 g/t Au and 37.69 g/t Ag; JW Zone infill

"Our 2017 resource expansion and exploration program has started off successfully, returning robust widths and grades that are typical for the Red Mountain Deposit," said Rob McLeod, President and CEO of IDM Mining. "The underground rigs are currently completing exploration holes up to 300 meters north of current resources, proximal to historic high-grade gold intercepts."

AV Zone

Drill holes U17-1228, 1229 and 1230 are all step-out holes completed on 25 meter centers, down-dip from the current AV zone resource; 25 meter spacing is the minimum spacing for Indicated Resource classification. All three holes intersected gold and silver mineralization, including U17-1229 which intersected (capped) 6.23 meters true width averaging 12.95 g/t Au and 48.83 g/t Ag. Drill hole U17-1231 is an updip hole, intersecting 5.00 meters true width of 8.78 g/t Au and 53.04 g/t Ag (capped).

JW Zone

Drill hole U17-1233 is an infill hole with the objective of boosting the grade of a portion of the JW zone. This hole intersected a true width of 25.00 meters averaging 8.92 g/t Au and 37.69 g/t Ag, including 2.00 meters averaging 89.70 g/t Au and 26.65 g/t Ag (uncapped), with coarse visible gold. The capped intercept for U17-1233 averaged 25.00 meters averaging 6.15 g/t Au and 37.69 g/t Ag.

Complete drill results are as follows:

Complete results are as follows:

* Assays capped at 55.0 g/t Au and 220 g/t Ag

** Drilled intervals estimated using approximate 3.0 g/t cut-off for underground mining

Drill hole collar information and location maps, core photos along with sample cross 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 will release shortly the results of a Feasibility Study for a high-grade, underground gold mine, which envisions 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.

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 with a diamond saw, and 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 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 and Yukon, with a primary focus on the high grade underground Red Mountain gold project which has entered the BC and Canadian environmental assessment process.

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.