Osisko Development Provides Infill Drilling Update ON Its 13,000- Meter Lowhee Program at Cariboo GOLD Project; Intercepts Include 45.24 G/T GOLD over 3.0 Meters, Including 233.92 G/T GOLD over 0.5 Meters
ODV NYSE TSXV News Release
www.osiskodev.com Page 1 of 10
OSISKO DEVELOPMENT PROVIDES INFILL DRILLING UPDATE ON ITS 13,000-
METER LOWHEE PROGRAM AT CARIBOO GOLD PROJECT; INTERCEPTS INCLUDE
45.24 g/t GOLD OVER 3.0 METERS, INCLUDING 233.92 g/t GOLD OVER 0.5
METERS
Montreal, Québec, October 6, 202 5 – Osisko Development Corp. (NYSE: ODV, TSXV: ODV)
("Osisko Development" or the "Company") is pleased to announce new infill drilling results from its
ongoing 13,000-meter program on 10 meter drill spacing that commenced in August 2025 in the Lowhee
Zone of the Company's permitted, 100%-owned Cariboo Gold Project (" Cariboo" or the " Project"),
located in central British Columbia (" B.C."), Canada. The first three fans of this program consisted of
approximately 2,279 meters ("m") of underground infill drilling.
Chris Lodder, President, stated , "We have observed good continuity consistent with modelled vein
zones and planned stope shapes with these initial results. The presence of high-grade composites within
and adjacent to modelled reserve stopes is encouraging and highlights the value of systematic
underground infill drilling . The success we are seeing underscores the potential and prospectivity of
delineating new zones and expanding existing ones near planned infrastructure, which could be drilled
off and incorporated into a future mine plan. The comprehensive 13,000-meter drill program is designed
to deliver important data for resource modelling, mine planning, and optimization of production stope
design. We look forward to providing further updates as drilling progresses."
DRILL ASSAY HIGHLIGHTS
This news release includes assays from twenty-four (24) underground infill and exploration HQ diamond
drill ("DD") holes (63.5-millimeter diameter) totaling approximately 2,279 m completed from August
2025 through early September 2025 (see Table 1) and for which assays were received by October 1,
2025, with depths ranging from 54 to 114 m drilled on 3 fans at 40 m spaced fans (Figure 2). Select
assay photon assay highlights include:
• 45.24 grams per tonne ("g/t") gold ("Au") over 3.0 m in hole BMU-25-075, including:
o 233.92 g/t over 0.5 m, and
o 35.19 g/t over 0.5 m
• 41.17 g/t over 2.1 m in BMU-25-065, including:
o 142.56 g/t over 0.5 m, and
o 19.20 g/t over 0.6 m, and
o 5.88 g/t over 0.5 m
HIGHLIGHTS
2,279 m of infill drilling completed on 10 -m drill spacing in 24 drill holes from August 2025
representing ~17.5% of the total planned 13,000-m infill program
Highlight intercepts include: 45.24 g/t Au over 3.0 m, including 233.92 g/t Au over 0.5 m, 41.17
g/t Au over 2.1 m, and 16.36 g/t Au over 4.6 m
Initial results show good continuity consistent with modelled vein zones and planned stopes,
including high-grade intercepts within and adjacent to modelled reserve stopes, reinforcing the
potential for delineating new zones and expanding existing ones
Systematic underground infill drilling is designed to derisk resource modelling, mine planning
and optimize production stope design
www.osiskodev.com Page 2 of 10
• 16.36 g/t over 4.6 m in BMU-25-079, including:
o 111.75 g/t over 0.5 m, and
o 25.03 g/t over 0.6 m, and
o 5.17 g/t over 0.5 m
• 38.92 g/t over 1.5 m BMU-25-073, including:
o 113.06 g/t over 0.5 m, and
o 3.17 g/t over 0.5 m
• 9.87 g/t over 3.95 m in BMU-25-085, including:
o 22.84 g/t over 0.6 m, and
o 13.78 g/t over 0.85 m, and
o 16.04 g/t over 0.5 m, and
o 5.22 g/t over 0.5 m, and
o 4.00 g/t over 0.5 m
• 5.67 g/t over 6.0 m in BMU-25-064, including:
o 17.95 g/t over 0.5 m, and
o 8.45 g/t over 1.0 m, and
o 11.38 g/t over 0.5 m, and
o 8.46 g/t over 0.5 m, and
o 6.99 g/t over 0.5 m, and
o 4.36 g/t over 0.5 m
• 7.06 g/t over 4.5 m in BMU-25-067, including:
o 39.00 g/t over 0.5 m, and
o 15.96 g/t over 0.5 m, and
o 3.82 g/t over 0.5 m
• 8.97 g/t over 3.5 m in BMU-25-078, including:
o 59.94 g/t over 0.5 m
• 9.18 g/t over 2.6 m in BMU-25-083, including:
o 23.51 g/t over 0.5 m, and
o 7.20 g/t over 1.0 m, and
o 7.87 g/t over 0.6 m
• 3.36 g/t over 7.0 m in BMU-25-071, including:
o 14.78 g/t over 0.5 m, and
o 11.19 g/t over 0.5 m, and
o 5.75 g/t over 0.5 m, and
o 3.29 g/t over 0.5 m, and
o 4.03 g/t over 0.5 m, and
o 3.88 g/t over 0.5 m
Complete assay highlights , including true width estimates, are presented in Table 1 and drill hole
locations and orientations are listed in Table 2. Intervals not recovered by drilling were assigned zero
grade. Top cuts have not been applied to high grade assays.
www.osiskodev.com Page 3 of 10
Figure 1: Cariboo Gold Project deposit map with Location of Lowhee Zone and Cow Portal underground access.
Figure 2: Location and overview of the ongoing 13,000-meter infill drilling campaign.
www.osiskodev.com Page 4 of 10
Figure 3: Lowhee Zone infill select underground drilling highlights, plan view.
Figure 4: Lowhee Zone infill select underground drilling highlights in cross section by fan.
www.osiskodev.com Page 5 of 10
Table 1: Length weighted assay composites and individual samples>=3.0 g/t for Lowhee Zone underground DD.
Drillhole ID From (m) To (m) Length (m) Au (g/t) Est. True Width (m)
BMU-25-061 No significant assays
BMU-25-062 72 72.5 0.5 4.87 0.41
81.3 81.8 0.5 13.70 0.41
BMU-25-063 No significant assays
BMU-25-064 56 62 6 5.67 5.75
Including 56 56.5 0.5 11.38
and 58 58.5 0.5 17.95
and 58.5 59 0.5 6.99
and 59.5 60 0.5 8.46
and 60 60.5 0.5 4.36
and 61 62 1 8.45
69 69.5 0.5 3.21 0.43
84.2 84.7 0.5 5.10 0.43
91.95 92.45 0.5 19.76 0.32
BMU-25-065 2.2 2.75 0.55 5.29 0.46
3.75 5.25 1.5 3.59 1.30
Including 4.65 5.25 0.6 6.98
10.7 12.2 1.5 4.19 1.36
Including 10.7 11.2 0.5 11.77
17.5 18 0.5 15.99 0.43
20.5 21.5 1 3.57 0.91
Including 21 21.5 0.5 6.64
41.05 41.6 1.1 4.44 0.48
48.1 49.6 1.5 6.61 1.44
Including 48.1 48.6 0.5 5.25
and 48.6 49.1 0.5 4.03
and 49.1 49.6 0.5 10.54
52.4 54.5 2.1 41.17 1.25
Including 52.4 52.9 0.5 5.88
and 52.9 53.4 0.5 142.56
and 53.4 54 0.6 19.20
BMU-25-066 16 16.5 0.5 3.51 0.47
54 54.5 0.5 6.67 0.47
75.7 76.2 0.5 4.83 0.47
BMU-25-067 0.7 2.7 2 3.63 1.29
Including 0.7 1.2 0.5 4.00
and 1.2 1.7 0.5 8.16
www.osiskodev.com Page 6 of 10
Drillhole ID From (m) To (m) Length (m) Au (g/t) Est. True Width (m)
9 10 1 11.09 0.94
Including 9.5 10 0.5 21.74
16.5 21 4.5 7.06 4.23
Including 16.5 17 0.5 15.96
and 17.5 18 0.5 39.00
and 20.5 21 0.5 3.82
47.5 48 0.5 3.55 0.32
54.35 54.85 0.5 10.25 0.45
93.9 96.5 2.6 5.56 2.29
Including 93.9 94.4 0.5 14.37
and 94.4 94.9 0.5 4.59
and 95.9 96.5 0.6 7.67
BMU-25-068 11 12 1 6.86 0.95
Including 11.5 12 0.5 13.38
27 27.5 0.5 4.06 0.49
43 43.5 0.5 4.94 0.49
57.5 58 0.5 3.76 0.49
62.5 63 0.5 4.28 0.49
64 66 2 3.13 1.97
Including 65 65.5 0.5 5.40
and 65.5 66 0.5 3.39
BMU-25-069 0.7 1.2 0.5 13.40 0.43
16.5 19.65 3.15 3.48 3.12
Including 17.6 18.15 0.55 15.63
and 19.15 19.65 0.5 3.08
36 36.6 0.6 7.55 0.54
41.3 42.45 1.15 8.64 1.08
Including 41.85 42.45 0.6 14.98
47 50.3 3.3 3.63 3.10
Including 48.3 48.8 0.5 21.51
53 54 1 3.83 0.87
Including 53 53.5 0.5 3.37
and 53.5 54 0.5 4.29
88.15 89.15 1 5.13 0.94
Including 88.15 88.65 0.5 8.48
BMU-25-070 37.5 38 0.5 9.73 0.43
BMU-25-071 10.5 11.5 1 4.45 0.94
Including 10.5 11 0.5 4.08
and 11 11.5 0.5 4.83 0.47
46.5 47.5 1 4.23 0.94
Including 46.5 47 0.5 7.91 0.47
58.5 59 0.5 4.73 0.48
64 71 7 3.36 6.98
Including 64.5 65 0.5 11.19
and 65.5 66 0.5 3.29
and 67.5 68 0.5 4.03
and 68 68.5 0.5 5.75
and 69.5 70 0.5 3.88
and 70 70.5 0.5 14.78
79.5 80 0.5 4.92 0.49
BMU-25-072 0.2 0.7 0.5 6.53 0.48
64.5 65 0.5 12.27 0.49
83 84 1 4.22 0.87
Including 83 83.5 0.5 8.09
BMU-25-073 9.2 9.7 0.5 3.48 0.50
21.5 22 0.5 10.15 0.45
47.5 48 0.5 4.27 0.47
52.5 54 1.5 38.92 1.49
Including 52.5 53 0.5 3.17
and 53.5 54 0.5 113.06
BMU-25-074 26.85 27.35 0.5 4.63 0.50
BMU-25-074 37.1 38.6 1.5 5.35 1.30
Including 37.1 37.6 0.5 13.16
67.5 68 0.5 3.87 0.48
BMU-25-075 BMU-25-075 71.5 74.5 3 45.24 2.38
Including 72 72.5 0.5 233.92
and 73.5 74 0.5 35.19
BMU-25-076 12.8 13.3 0.5 19.24 0.45
BMU-25-077 27.05 27.55 0.5 10.96 0.50
41.15 41.65 0.5 29.90 0.45
43.85 45.35 1.5 3.34 1.50
Including 43.85 44.35 0.5 5.79
and 44.85 45.35 0.5 3.97
47.25 47.75 0.5 28.26 0.50
67 68 1 5.69 1.00
Including 67.5 68 0.5 10.99
www.osiskodev.com Page 7 of 10
Drillhole ID From (m) To (m) Length (m) Au (g/t) Est. True Width (m)
BMU-25-078 BMU-25-078 27.85 31.35 3.5 8.97 3.17
Including 30.85 31.35 0.5 59.94
BMU-25-078 44.8 45.8 1 3.13 1.00
Including 45.3 45.8 0.5 4.32
BMU-25-079 BMU-25-079 28.1 28.6 0.5 39.84 0.35
BMU-25-079 85.2 89.8 4.6 16.36 3.98
Including 85.7 86.2 0.5 5.17
and 86.2 86.8 0.6 25.03
and 89.3 89.8 0.5 111.75
BMU-25-080 No Significant Assays
BMU-25-081 BMU-25-081 43.5 45.5 2 4.06 1.73
Including 43.5 44 0.5 7.89
and 44 44.5 0.5 7.00
66.5 67.2 0.7 6.75
BMU-25-082 No Significant Assays
BMU-25-083 BMU-25-083 1.35 2.5 1.15 3.40 1.06
Including 1.35 2 0.65 5.12
51.9 52.4 0.5 34.55 0.38
BMU-25-083 60.5 63.1 2.6 9.18 2.28
Including 61 62 1 7.20
and 62 62.5 0.5 23.51
and 62.5 63.1 0.6 7.87
BMU-25-085 56.6 57.1 0.5 26.70 0.41
BMU-25-085 69.45 73.4 3.95 9.87 3.58
Including 69.45 69.95 0.5 4.00
and 69.95 70.8 0.85 13.78
and 71.8 72.3 0.5 16.04
and 72.3 72.9 0.6 22.84
and 72.9 73.4 0.5 5.22
Table 2: Underground DD collar locations, drillhole orientations, and max depths. Negative dips point down.
Drillhole ID Mine Location Easting
(UTM z12N)
Northing
(UTM z12N)
Elevation
(m)
Dip Azimuth Depth
(m)
BMU-25-061 L1260-ORE-003-DBY-008 596468.7 5882768.6 1262.3 -35 125 114
BMU-25-062 L1260-ORE-003-DBY-004 596488.9 5882802.9 1261.0 -35 125 114
BMU-25-063 L1260-ORE-003-DBY-008 596468.4 5882768.8 1261.6 -25 125 102
BMU-25-064 L1260-ORE-003-DBY-004 596488.9 5882803.0 1260.2 -25 125 102
BMU-25-065 L1260-ORE-003-DBY-000 596510.0 5882837.7 1259.8 -35 125 114
BMU-25-066 L1260-ORE-003-DBY-004 596488.9 5882803.0 1259.8 -15 125 80
BMU-25-067 L1260-ORE-003-DBY-000 596510.1 5882837.6 1259.4 -25 125 102
BMU-25-068 L1260-ORE-003-DBY-004 596488.9 5882802.9 1259.3 -5 125 81
BMU-25-069 L1260-ORE-003-DBY-000 596510.1 5882837.6 1258.7 -14 125 96
BMU-25-070 L1260-ORE-003-DBY-008 596468.8 5882768.6 1261.2 -15 125 84
BMU-25-071 L1260-ORE-003-DBY-004 596489.1 5882802.9 1258.9 5 125 81
BMU-25-072 L1260-ORE-003-DBY-000 596510.1 5882837.6 1257.3 25 125 90
BMU-25-073 L1260-ORE-003-DBY-004 596489.1 5882802.8 1258.6 15 125 54
BMU-25-074 L1260-ORE-003-DBY-008 596468.8 5882768.5 1260.7 -5 125 81
BMU-25-075 L1260-ORE-003-DBY-004 596489.2 5882802.8 1258.2 25 125 90
BMU-25-076 L1260-ORE-003-DBY-004 596489.2 5882802.9 1258.0 35 125 99
BMU-25-077 L1260-ORE-003-DBY-008 596469.1 5882768.4 1260.4 5 125 81
BMU-25-078 L1260-ORE-003-DBY-008 596469.0 5882768.4 1260.1 15 125 84
BMU-25-079 L1260-ORE-003-DBY-000 596510.0 5882837.6 1257.0 35 125 99
BMU-25-080 L1260-ORE-003-DBY-004 596489.0 5882803.0 1257.7 45 125 114
BMU-25-081 L1260-ORE-003-DBY-008 596468.9 5882768.5 1259.8 25 125 90
BMU-25-082 L1260-ORE-003-DBY-000 596510.2 5882837.8 1256.8 45 125 114
BMU-25-083 L1260-ORE-003-DBY-008 596468.7 5882768.6 1259.6 35 125 99
BMU-25-085 L1260-ORE-003-DBY-008 596468.3 5882768.9 1259.8 45 125 114
ABOUT LOWHEE ZONE
Geological mapping and geochemical sampling were carried out on Barkerville Mountain from 2017 -
2018, with the Lowhee Zone identified as a high-priority drill target.
In 2019, two southeast-oriented stratigraphic and 22 northwest-southeast oriented drillholes (8,337.0
m) were drilled at the Lowhee Zone. The drilling successfully identified auriferous quartz-carbonate veins
at similar orientations to those observed elsew here on the Cariboo Gold project. Initial 3D geological
modelling and resource estimation commenced, and further drilling was recommended.
In 2020, 24 northwest -oriented diamond drillholes (10,144.5 m) were drilled. The focus of the
exploration program was to test the extent of mineralization along the down -dip and northeast strike-
www.osiskodev.com Page 8 of 10
extent of veining. An internal resource estimation of the Lowhee deposit was completed at that time,
with further drilling recommended to improve confidence.
In 2021, a total of 94 diamond drillholes (29,449.1 m) were drilled. The focus of drilling was to delineate,
and infill modelled veins with 25 m spacing. At the time, Barkerville Gold Mines Ltd. completed a mineral
resource estimate, and the collection of a bulk sample was recommended.
In 2022, a total of 27 diamond drillholes (6,563.90 m) were drilled. There were two main goals with this
drill program. The first goal was to infill a potential bulk sample location achieving category conversion
from indicated (25 m spacing) to measured (12.5 m spacing). The second goal was to continue to
delineate and infill modelled veins with 25 m spacing.
Lowhee zone access is through Cow portal on the northwestern flank of Barkerville Mountain ( Figure 1
and Figure 2) Cow portal construction was completed in Q4 2024 and development of the underground
ramp into the Lowhee zone commenced in Q1 202 5. Approximately 350 m of development has been
advanced within the Lowhee zone deposit at the 1,290 and 1,260 -elevation levels since completion of
the main access ramp. The probable mineral reserves estimate for the Lowhee Zone includes 104,491
ounces of contained Au (923,162 tonnes grading 3.52 g/t Au) and represents approximately 5% of the
total contained gold in the estimated probable mineral reserves for the Cariboo Gold Project.
ABOUT CARIBOO GOLD PROJECT
The Cariboo Gold Project is a permitted , 100%-owned feasibility-stage project located in the historic
Wells-Barkerville mining camp of central British Columbia, Canada . Spanning approximately 18 6,740
hectares, the Company's land package includes 443 mineral titles and covers a ~77-kilometre strike of
highly prospective exploration targets extending northwest to southeast. In late 2024, the Project was
granted the Mines Act and Environmental Management Act (British Columbia) permits, marking the
successful completion of the permitting process for key approvals, solidifying the Project's shovel-ready
status.
The Cariboo Gold Project hosts probable mineral reserves of 2.07 million ounces of contained Au (17,815
kt grading 3.62 g/t Au); measured mineral resources of 8,000 ounces of contained Au (47 kt grading
5.06 g/t Au); indicated mineral resources of 1.60 million ounces of contained Au (17,332 kt grading
2.88 g/t Au); and inferred mineral resources of 1.86 million ounces of contained Au (18,774 kt grading
3.09 g/t Au). Mineral resources are reported exclusive of mineral reserves.
Technical Reports
Information relating to the Cariboo Gold Project and the 2025 FS on the Cariboo Gold Project is
supported by the technical report, titled "NI 43-101 Technical Report, Feasibility Study for the Cariboo
Gold Project, District of Wells, British Columbia, Canada " and dated June 11, 2025 (with an effective
date of April 25, 2025) (the "Cariboo Technical Report").
For readers to fully understand the information in the Cariboo Technical Report, reference should be
made to the full text of the Cariboo Technical Report in its entirety, including all assumptions,
parameters, qualifications, limitations and methods therein. The Technical Report is intended to be read
as a whole, and sections should not be read or relied upon out of context. The Technical Report was
prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects
("NI 43 -101") and is available electronically on SEDAR+ ( www.sedarplus.ca) and on EDGAR
(www.sec.gov) under Osisko Development's issuer profile and on the Company's website at
www.osiskodev.com.
Qualified Persons
The scientific and technical information contained in this news release has been reviewed , verified and
approved by Eryn Doyle, P. Geo., Senior Exploration Manager of Osisko Development, a "qualified
person" within the meaning of NI 43-101. Verification includes core photo and three-dimensional review
of logged drillhole data and assays consistent with the Company's standard procedures.