IDM Mining Discovers New Vein: Samples 22.2 g/t Au and 81.3 g/t Ag over 9.35 meters in Subcrop at Lost Valley, Red Mountain Project

September 12, 2016, Vancouver, BC - IDM Mining Ltd. (TSX.V:IDM) ("IDM" or the "Company") is pleased to announce that surface hand trenching has discovered the Randell Zone, another strongly mineralized structure at its Red Mountain Gold Project ("Red Mountain" or the "Property"). This new zone is located less than 100 meters to south of, and stacked above, the Anda'adala'a Lo'op Zone.

"This latest discovery suggests a series of stacked, high-grade, shallow-dipping structures with significant widths," said Rob McLeod, President and CEO of IDM Mining. "Lost Valley is at the headwaters of Bitter Creek, the location of the first alluvial gold discoveries in the Stewart area at the turn of the 20th Century."

LOST VALLEY PROSPECT

High-grade structures in the Lost Valley area ("Lost Valley") were identified earlier in the 2016 field season. Assays have been received from surface trenching at the Randell Zone, named in honor of consulting geologist Andy Randell; mineralization occurs as a subcrop slope several meters high, of weathered fragments of quartz, sulphide and altered monzogranite. The mineralization occurs at the base of a cliff, and is partly covered by talus and glacial erratics. A hand trench was excavated, and a continuous 9.35 meters long channel sample of the subcrop averaged 22.2 g/t Au and 81.3 g/t Ag, including 0.85 meters of 133.25 g/t Au and 378 g/t Ag. Select grab samples include 0.87, 3.14, 24.70, 30.3 and 133.0 g/t Au.

The style of mineralization is comparable to the Anda'adala'a Lo'op Zone, which outcrops approximately 100 meters to the northwest, and about 20 meters lower in elevation. This structure has been traced for a total of 78 meters on surface and remains open in all directions. Channel samples averaged 18.7 g/t Au and 61.4 g/t Ag over an average width of 0.84 meters, with individual assays of up to 34.6 g/t Au, 183.0 g/t Ag. (see IDM News Release August 24, 2016). The total thickness of both mineralized structures, likely related to stacked thrust faults is not known. Further below the Anda'adala'a Lo'op Zone, in a creek at the base of the Lost Valley cirque, a single outcrop entirely comprised of quartz and sulphide return 5.18 g/t Au and

42.0 g/t Ag across 3.0 meters. All three occurrences, coupled with high-grade, shallow dipping veins identified throughout the Lost Valley area, suggest a series of stacked structures. Gold- silver mineralization coincides with anomalous concentrations of bismuth, copper, molybdenum and tellurium.

Lost Valley is located approximately four kilometers southwest of the Marc/AV/JW zones which make up the primary reported resource at Red Mountain, with ongoing underground Diamond drilling. IDM intends to commence drilling at Lost Valley during the next month.

Much of the Lost Valley prospect was covered by ice during the initial discovery of the Red Mountain deposit in the 1990's (see IDM news release, dated July 19, 2016). Lost Valley is underlain by an Eocene multi-phase monzogranite that is similar in age to other molybdenum- bearing porphyry systems in the region, including the Kitsault molybdenum deposit about 55 kilometers to the south. Molybdenum, pyrite and chalcopyrite mineralization is widespread throughout the intrusion and the surrounding biotite-hornfelsed argillite and tuff. Assays of up to 3.45% Mo and 1.65 g/t Re have been reported from select samples (IDM news release, dated

July 19, 2016). In addition to the molybdenum mineralization, sheeted sets of banded quartz- sulphide veins are associated with later stage brittle faults and veins throughout the intrusion and the surrounding wall rocks. High grade gold, silver and copper mineralization is found within these veins which assay up to 165 g/t Au, 1,048 g/t Ag and 15.5% Cu. The veins vary from 5 to 100 centimeters in width and are traceable for up to a kilometer along strike.

Maps and photos from Lost Valley 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. Discovered in 1989, the property was explored extensively until 1996 by Lac Minerals Ltd. and Royal Oak Mines Inc., with 466 Diamond drill holes and over 2,000 meters of underground development completed, along with extensive engineering and environmental baseline work.

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

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

QA/QC AND QUALIFIED PERSON

Samples for the 2016 exploration program are collected by experienced geologists and technicians, 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 2016 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 43-10. 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. Further information can be found on the Company's website at www.IDMmining.com

ON BEHALF OF THE BOARD

of IDM Mining Ltd. "Robert McLeod"

President, CEO and Director

For more information, contact: Robert McLeod

604-681-5672 direct

604-617-0616 cell

[email protected]

Investor Relations:

Shobana Thaya Alex Horsley

[email protected] [email protected]

416-807-1009 604 484-7855

"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.