Osisko Metals Releases Exceptional Flotation Test Work Results at Pine Point

Jeff Hussey, P. Geo., Osisko Metals President and CEO, commented: “These preliminary results are outstanding and confirm that the zinc concentrates originally produced at Pine Point were amongst the cleanest in the world. Using conventional flotation, we were able to achieve exceptional recoveries as well as concentrate grade and quality. We do not anticipate any smelter or refinery penalties should Pine Point go into production. We believe the Pine Point zinc concentrate would be a premium blending product in the zinc concentrate market which is forecasted to be dominated by much lower quality concentrates.”

Robert Wares, P. Geo., Osisko Metals Executive Chairman, also commented: “I am very impressed by these initial test results – quite frankly the best I have seen in my career. The Pine Point deposit is growing into a major zinc project with significant near-surface resources, excellent concentrate grades and recoveries, ready access and existing infrastructure, all within a safe Canadian jurisdiction. We expect to expand the resources this year with additional drilling that will be underway by the end of this quarter.”

Summary results

Rougher Flotation Test Work

Cleaner Flotation Test Work

Concentrate Analysis (optimized cleaner product)

• Zinc concentrate is below penalty threshold for all deleterious impurities except MgO
• Zinc concentrate grades ranged between 63.6% to 64.1% Zn
• Lead concentrate grades ranged between 67.9% to 72.1% Pb

Flotation Test Work Details

Froth flotation tests were performed with various XRT material sorter concentrates from the East Mill and Central Zones. The first set of rougher flotation tests was performed using historical grind size (75 microns), reagents and dosage levels used by Pine Point (Cominco Ltd.). The results are shown in the following table:

Table 1: Initial Rougher Flotation Test Work

Initial test work confirmed very high recoveries for lead. However, further optimization was deemed necessary to improve the zinc recovery by capturing the significant zinc units that were reporting to the lead concentrate in the initial rougher flotation test work.

To optimize zinc recovery in the rougher flotation cells for this type of mill feed material, a new simplified suite of reagents was used. This suite was used to test three samples that represent the Life of Mine (“LOM”) concentrate produced by the XRT material sorter. The sorted material is expected to have approximately twice the average zinc + lead grade when compared to the mill feed mineralization that was reported in the Pine Point Mineral Resource Estimate that was announced in December of 2018.

Table 2: Optimized Rougher Flotation Test Work

Zinc recovery improved significantly without any detrimental impact on the lead recovery.

Rougher flotation concentrates from the optimization program were reground and re-floated or “cleaned” to evaluate final concentrate metal grades and recoveries that would be achievable. Similar to the initial rougher flotation testing, historical grind size (75 microns), reagents and dosages were used as a starting point.

Table 3: Initial Cleaner Flotation Test Work

High concentrate grades were achieved after two stages of cleaning. Additional cleaning test work was performed using various reagents to investigate potential further improvements. An additional cleaning test was performed on reground concentrate material (35 microns for the Zn con and 20 microns for Pb con) while another analytical test was performed without the regrind stage.

Table 4: Optimized Cleaner Flotation Test Work

The optimization of the cleaner flotation test work improved the final zinc recovery without negatively impacting the final zinc concentrate grade. Rougher concentrate regrinding before the cleaning stage seems to have a more significant impact on the final lead concentrate grade than the zinc concentrate grade.

Future test work will aim to measure the impact of regrinding on the lead recovery circuit. Based on future results, trade-off studies will determine if a regrind stage is worthwhile.

All metal recovery values cited in this press release are unit recoveries achieved after pre-concentration and do not represent the overall metal recoveries which should combine pre-concentration and flotation recoveries. Overall recoveries are expected to be lower than those reported in this news release due to metal losses in the pre-concentration process. However, Osisko Metals is currently advancing trade-off studies to determine the profitability of pre-concentration.

Zinc Concentrate Analysis Details

A sample of optimized cleaner zinc concentrate was sent for further analysis to measure concentrations of potentially deleterious elements commonly associated with smelter penalties. Historically, Pine Point concentrates produced over its 24-year mine life were known to contain very low levels of deleterious elements, except for Magnesium Oxide which is associated with the dolomitic host rock. Initial testing of the zinc concentrate indicates that Magnesium Oxide is at the current smelter penalty threshold. Further test work will incorporate methods on decreasing the magnesium concentration. These results support Pine Point’s historical production data and confirms the very low levels of impurities in the zinc concentrate.

At this time, Osisko Metals does not anticipate any smelter or refinery penalties for Pine Point zinc concentrate that could be produced from a potential mining operation. Table 5 summarizes the main deleterious elements analyzed and lists the typical minimal threshold for smelter penalties:

  Table 5: Concentrate Elemental Analysis

* Indicates analytical result below detection limits
º Source: Wood Mackenzie

About Osisko Metals

Osisko Metals is a Canadian exploration and development company creating value in the base metal space with a focus on zinc mineral assets. The Corporation controls Canada's two premier historical zinc mining camps: The Pine Point Mining Camp and the Bathurst Mining Camp. The Pine Point Mining Camp is located on the south shore of Great Slave Lake in the Northwest Territories, near established infrastructure, with paved highway access and 100 kilometres of mine haulage roads and power substation already in place. The Pine Point Mining Camp currently hosts an inferred mineral resource (for purposes of National Instrument 43-101 – Standards of Disclosure for Mineral Projects) of 38.4 Mt grading 4.58% zinc and 1.85% lead, making it the largest near-surface, pit-constrained zinc deposit in Canada (please refer to the technical report titled "Mineral Resource Estimate for the Pine Point Lead-Zinc Project, Hay River, Northwest Territories, Canada" dated as of January 18, 2019, as amended and restated as of January 25, 2019 (with an effective date of December 20, 2018) prepared by BBA Inc. for Osisko Metals, a copy of which is available on SEDAR (www.sedar.com) under Osisko Metals' issuer profile. The 2018-2019 drill holes, once fully assayed, will be incorporated into the database with the objective of issuing a new resource estimate in the second half of 2019. The Bathurst Mining Camp is located in northern New Brunswick, with an indicated mineral resource (for purposes of National Instrument 43-101 – Standards of Disclosure for Mineral Projects) of 1.96 Mt grading 5.77% zinc, 2.38% lead, 0.22% copper and 68.9g/t silver (9.00% ZnEq) and an inferred mineral resource (for purposes of National Instrument 43-101 – Standards of Disclosure for Mineral Projects) of 3.85 Mt grading 5.34% zinc, 1.49% lead, 0.32% copper and 47.7 g/t silver (7.96% ZnEq) in the Key Anacon and Gilmour South deposits. In Québec, Osisko Metals owns 42,000 hectares that cover 12 grass-root zinc targets that will be selectively advanced through exploration in 2019.

Technical Information, QA/QC and Qualified Persons

Metallurgical program design, monitoring and sample preparation were completed under the supervision of Mr. Christian Laroche, P. Eng. and Mr. Robin Adair, P.Geo., both Qualified Persons as defined by National Instrument 43-101.

Metallurgical testing and analyses were performed at SGS Mineral Services in Burnaby, British-Columbia, Canada. Concentrate elemental analysis was also performed at ALS Canada in North Vancouver, British Columbia, Canada using four-acid digestion and ICP-MS. The QA/QC program utilized is consistent with NI 43-101 and industry best practice standards. The technical information in this news release was reviewed and approved by Mr. Christian Laroche, P.Eng.  and Mr. Robin Adair, P.Geo. both Qualified Persons as defined by National Instrument 43-101.

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

Cautionary Note Regarding Forward-Looking Information

This news release contains "forward‐looking information" within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. The information in this news release about the Offering; the use of the proceeds from the Offering; the jurisdictions in which the Flow-Through Shares are offered or sold; the number of Flow-Through Shares offered or sold; the gross proceeds from the Offering; the timing and ability of the Corporation to close the Offering, if at all; the timing and ability of the Corporation to satisfy the listing conditions of the TSX Venture Exchange, if at all; the tax treatment of the Flow-Through Shares; the timing of the renounce of the Qualifying Expenditures in favor of the subscribers, if at all; the results of the 2018-2019 drill holes; the timing and ability of the Corporation to issue a new resource estimate in the second half of 2019, if at all; the prospects of the Pine Point Mining Camp and the Bathurst Mining Camp; and any other information herein that is not a historical fact may be "forward-looking information". Any statement that involves discussions with respect to predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as "expects", or "does not expect", "is expected", "interpreted", "management's view", "anticipates" or "does not anticipate", "plans", "budget", "scheduled", "forecasts", "estimates", "believes" or "intends" or variations of such words and phrases or stating that certain actions, events or results "may" or "could", "would", "might" or "will" be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This forward-looking information is based on reasonable assumptions and estimates of management of the Corporation, at the time such assumptions and estimates were made, and involves known and unknown risks, uncertainties or other factors which may cause the actual results, performance or achievements of the Corporation to be materially different from any future results, performance or achievements expressed or implied by such forward-looking information. Such factors include, among others, risks relating to the Offering; volatility in the trading price of common shares of the Corporation; risks relating to the ability of the Corporation to obtain required approvals, complete definitive documentation and complete the Offering on the terms announced; ability of Osisko Metals to complete further exploration activities; property interests; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks changes in the tax and regulatory regime; and community and non-governmental actions. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions, the Corporation cannot guarantee shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Corporation nor any other person assumes responsibility for the accuracy and completeness of any such forward looking information. Corporation does not undertake, and assumes no obligation, to update or revise any such forward looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.