Osisko Mining ehem. Oban Mining Corp. WKN: A14Y5V

President and Chief Executive Officer John Burzynski commented: “We are highly encouraged with the excellent results from this second bulk sample completed from the Windfall deposit. The average grade greatly exceeded our expectations based on the infill drilling, returning 89% higher grade than anticipated. The significant grade increase from the block model appears to correspond well with the very regular visible gold observed in Lynx drilling. The bulk sampling work is greatly helping to build our confidence in the continuity, grade, recoveries and the predictability of the mineralized zones at Windfall.”

Geology
The Lynx zone 311 bulk sample is characterized by an East-North-East sub vertical silica altered corridor with an average width of approximately 2.5 meters. Banded grey quartz veins contain 3 to 15% disseminated pyrite and local visible gold, cross-cutting foliated rhyolite and granodiorite with strong sericite and local fuchsite alteration. The continuous vein system was mapped along sills over three levels.

Processing
A total of 5,716 tonnes were processed in November 2019. The bulk sample test was performed at the Northern Sun Redstone concentrator. Processing produced gravity and flotation concentrates. Ore transportation trucks were sampled for moisture and weighed on a calibrated weight scale. The sample material was crushed and milled to a particle size favorable to the flotation recovery process. Gravity and flotation concentrates produced will be sent to a local smelter for sale. Day and night shift daily composite samples of streams for the reconciliation process were prepared and analyzed by an external independent lab. Concentrate production tonnage and assays were used to reconcile the bulk sample mass balance process in the concentrator. The reconciliation was performed by an external independent consultant using Bilmat (a reconciliation software) on a dry tonnes basis.

The reconciled head grade obtained from the processed sample is 17.8 g/t Au and 11.8 g/t Ag. The sample contained 3,271 oz Au and 2,176 oz Ag, with a total of 3,181 oz Au and 2,052 oz Ag recovered. Reconciled recoveries are 97.2% for gold and 94.3% for silver. The Preliminary Economic Assessment (or “PEA”, see Osisko news release dated July 17th, 2018) metallurgical test work considered a communition, gravity and carbon in leach process flowsheet, giving an average recovery of 93.8% for Lynx zone. Test mill availability dictated the use of a mill with a communition, gravity and flotation flowsheet. The reconciled results from the processing of the bulk sample material are presented in Table 1 below:

Table 1: Lynx Bulk Sample Reconciled Results
tonnes (dry) Head
Grade Contained
Ounces Gravity Concentrate Flotation Concentrate Overall
Recovery Recovered
Ounces
Au (g/t) Ag (g/t) Au Ag tonnes (dry) Au Rec (%) tonnes (dry) Au Rec (%) Au Recovery (%) Ag Recovery (%) Au Ag
5,716 17.8 11.8 3,271 2,176 9.7 66.7 284.4 91.7 97.2 94.3 3,181 2,052
Mill feed tonnages used in the sample processing reconciliation were provided by Northern Sun. Day and night shift daily composite samples collected during the processing of the bulk sample were assayed by external independent laboratories. Bulk sample results were reconciled by Soutex Inc., an external independent consultant using Bilmat.

Block Model
The area mined was located in mineralization wireframe 311 from the Windfall Lynx updated resources block model. The area was prepared for mining with infill drilling at 12.5 metre spacing. The same parameters used in the November 2018 Mineral Resource Estimation (see Osisko news release dated November 28, 2018) were used for an internal update of the resource block model in the bulk sample area. The infill drilling block model predicted 5,717 tonnes at 9.40 g/t Au containing 1,736 ounces of gold inside the excavated area (see Table 2 below).

Table 2: Infill Resource Block Model Predictions vs. Actual Processed
Predicted from Block Model
(12.5m Infill Spacing) Actual Processed Material
Tonnes Au g/t Au Ounces Tonnes Au g/t Au Ounces
5,717 9.40 1,736 5,716 17.8 3,271

Concentrates
Both the gravity concentrate and flotation concentrate produced from the sample are considered high-grade. The gravity concentrate averaged 7,020 g/t Au (225.7 oz/T Au), while the flotation concentrate averaged 110.6 g/t Au (3.6 oz/T Au), or respectively CDN$381,464/t and CDN$6,010/t (using US$1300/oz and 1.3 US/CDN exchange rate). Further work will be conducted on the process flowsheet prior to feasibility in light of these high-value numbers.

Mining and Grade Control
The Lynx bulk sample was mined in wireframe 311 with the long hole mining method proposed in the PEA. Two development drifts were mined conventionally at 20 metre vertical intervals between 210 and 230 meters below surface. A third development drift was mined 20 metres above the stope at 190 meters below surface to confirm grade and continuity of the Lynx 311 wireframe. While mining the development drifts, split blasts of the face were completed to test the width and grade of the mineralization. A V30 borehole was used in the slot raise and two and one-half inch production holes were drilled down and blasted. The blasted ore was retrieved with remote scoop tram equipment and trucked to the mill with muck samples taken.