Osisko Development Announces Mineral Resource
NYSE | TSXV: ODV NEWS RELEASE
Page 1 of 10
OSISKO DEVELOPMENT ANNOUNCES MINERAL RESOURCE UPDATE FOR THE
TRIXIE DEPOSIT, TINTIC PROJECT
• Measured resources of 119,847 tonnes grading 27.36 grams per tonne (" g/t") gold ("Au")
and 61.73 g/t silver ("Ag"), for a total of 105,437 ounces ("oz") Au and 237,868 oz Ag.
• Indicated resources of 124,743 tonnes grading 11.17 g/t Au and 59.89 g/t Ag, for a total of
44,811 oz Au and 240,211 oz Ag.
• Inferred resources of 201,603 tonnes grading 7.80 g/t Au and 48.55 g/t Ag, for a total of
50,569 oz Au and 314,678 oz Ag.
Montreal, Québec, March 15, 202 4 – Osisko Development Corp. (NYSE: ODV, TSXV: ODV)
("Osisko Development " or the "Company") announces an updated mineral resource estimate
("MRE") for its 100% -owned underground Trixie deposit (the " 2024 Trixie MRE "), within the
Company's wider Tintic Project (" Tintic" or the " Tintic Project"), located in the historic East Tintic
Mining District in central Utah, U.S.A. The 2024 Trixie MRE incorporated an additional 1,674 underground
chip samples over 1,678 meters ("m") (5,507 feet ("ft")) of underground development, and 7,385 m of
drilling (24,229 ft) in 122 holes completed by the Company since the release of the initial Trixie MRE
(the "2023 Trixie MRE"), with an effective date of January 10, 2023.
Relative to the 2023 Trixie MRE, contained gold ounces in measured and indicated resources decreased
by 29% and inferred resources decreased by 79% primarily due to lower estimated grades that
incorporated an updated geologic model interpretation and conversion of inferred resources. Drill results
and underground mapping from the 2023 exploration program improved the knowledge of the extent
and distribution of mineralization , resulting in m odeling improvements to both mineralization and the
historical mine shape model.
Chris Lodder, President, stated, "The 2024 Trixie MRE incorporates changes to our interpretation of
the main mineralized structures and reflects better understanding of the structural controls of the
deposit and realistic mining parameters following our exploration and test mining work in 2023. To date
exploration and mining occurred on less than 10% of known mineralized structures in the west Tin tic
district and thus, we see significant precious metal potential at depth , on parallel structures to Trix ie,
along the Trixie and Sioux Ajax faults to the north and south, as well as around all historic high-grade
gold mines in the West Tintic District. These high-grade gold targets, combined with the copper-gold
porphyry potential where drilling is underway, and a large area of polymetallic carbonate replacement
potential, illustrate that we have only scratched the surface in understanding the overall metal
endowment potential of the Tintic district."
Table 1: 2024 Trixie MRE (all zones) – March 14, 2024
Classification Tonnes
(000's)
Au Grade
(g/t)
Contained
Gold
(000's oz)
Ag Grade
(g/t)
Contained
Silver
(000's oz)
Measured 120 27.36 105 61.73 238
Indicated 125 11.17 45 59.89 240
Measured and Indicated 245 19.11 150 60.80 478
Inferred 202 7.80 51 48.55 315
Notes (applicable to Tables 1, 2, and 3)
1. Effective date of the 2024 Trixie MRE is March 14, 2024.
Page 2 of 10
2. Each of Mr. William Lewis , P.Geo., of Micon International Limited and Alan J . San Martin, MAusIMM(CP), of Micon
International Limited (i) has reviewed and validated the 2024 Trixie MRE, (ii) is considered to be independent of the
Company for purposes of Section 1.5 of National Instrument 43 -101 – Standards of Disclosure for Mineral Projects ("NI
43-101"), and (iii) is a "qualified person" within the meaning of NI 43-101.
3. The mineral resources were estimated using the Canadian Institute of Mining (" CIM"), Metallurgy and Petroleum's " CIM
Definition Standards on Mineral Resources and Mineral Reserves" adopted by the CIM council.
4. Mineral resources are reported when they are within potentially mineable shapes derived from a stope optimizer algorithm,
assuming an underground longhole stoping mining method with stopes of 6.1 m x 6.1 m x minimum 1.5 m dimensions.
5. Mineral resources that are not mineral reserves do not have demonstrated economic viability.
6. Geologic modelling was completed by Osisko Development modeling geologist Jody Laing, P.Geo, using Leapfrog Geo
software. The 2024 Trixie MRE was completed by Osisko Development chief resource geologist, Daniel Downton, P.Geo
using Datamine Studio RM 2.0 software. William Lewis and Alan J. San Martin of Micon International Limited independently
reviewed and validated the mineral resource model.
7. The estimate is reported for an underground mining scenario and with USD assumptions. The cut-off grade of 4.32 g/t Au
was calculated using a gold price of US $1,750/oz, a CAD:USD exchange rate of 1.3 0; total mining, processing and G&A
costs of US $168.04/imperial ton ; a refining cost of US $2.65/ounce; a combined royalty of 4.5 0%; and an average
metallurgical gold recovery of 80%.
8. The stope optimizer algorithm evaluated the resources based on a gold equivalent grade which incorporates the silver grade
estimate and assumes a silver price of US$23/oz and metallurgical silver recovery of 45%.
9. The 2024 Trixie MRE is comprised of six zones within the greater Trixie area: T2, T3, T4, Wild Cat, 40 Fault and 75-85.
10. Average bulk density values in the mineralized domains were assigned to the T2 (2.955 T/m3), T3 (2.638 T/m3), T4(2.618
T/m3), Wild Cat, and 40 Fault (2.621 T/m3), and 75-85 (2.617 T/m3) domains.
11. Inverse Distance Squared interpolation method was used with a parent block size of 1.2 m x 2.4 m x 2.4 m.
12. The Company intends to file a technical report (the "Technical Report") in respect of the 2024 Trixie MRE in accordance
with NI 43-101 on SEDAR+ (www.sedarplus.ca) and on EDGAR (www.sec.gov) under Osisko Development's issuer profile
within 45 days of the date of this news release.
13. The 2024 Trixie MRE results are presented in -situ. Calculations used metric units (metres, tonnes, g/t). The number of
tonnes is rounded to the nearest thousand. Any discrepancies in the totals are due to rounding effects.
14. Neither the Company nor Micon International Limited is aware of any known environmental, permitting, legal, title-related,
taxation, socio-political, marketing or other relevant issue that could materially affect the mineral resource estimate other
than disclosed in this news release.
15. Technical information in this news release differs from similar information made public by U.S. companies subject to the
reporting and disclosure requirements of the U.S. Securities and Exchange Commission. See below under "Cautionary
Statement to U.S. Investors".
TRIXIE MINERAL RESOURCE ESTIMATE
• The 2024 Trixie MRE comprises six mineralized zones within the greater Trixie deposit, including
T2, T3, T4, Wild Cat, 40 Fault and 75 -85 over a strike length of 530 m, a maximum width of
105 m and to a maximum depth of 195 m for the deposit and is 350 m from surface (see cross
section Figure 1). These dimensions are for the overall size of the mineralized zone structures ,
with the 2024 Trixie MRE blocks contained within a smaller 440 m strike length, 60 m total width
and 195 m depth footprint.
• Gold mineralization is associated with high sulphidation epithermal mineralization, structurally
controlled and hosted within the quartzites. Mineralization consists of native Au, and rare Au-Ag
rich telluride minerals with quartz and quartz-barite-sulphosalt stockwork veining.
• The T2 Zone is the highest-grade structure within the overall deposit. In 2023, a total of 4,637
oz were recovered from processing mineralized material with an overall feed grade of 35.61 g/t
Au. The 2023 drill program also converted ounces from inferred to indicated, and drilling at
depth indicated a transition from high -grade gold to anomalous copper , which prompted the
testing of the deep porphyry target at Trixie West.
• The T4 Zone envelops the T2, 40 fault, and Wild Cat domains. Within the T4 domain, there are
discrete sub -vertical high -grade gold structures, defined on multiple levels and sections.
However, these structures appear to be more discontinuous and less disseminated in the broader
area than had been previously estimated . In 2023, mapping and modeling modified the
interpretation from a stockwork to distinct high -grade structures. As a result, the model now
incorporates tight search parameters around these structures, increasing confidence within the
zone, while also including the quartz-barite-sulphosalt disseminated stockwork mineralization.
o A mineralized fault structure known as the 40 fault, is mapped over 230 m strike
length and 80 m at depth and is about 1 m wide. This fault is a mineralized domain
within the T4 and offsets vertically dipping epithermal Au-Ag structures.
Page 3 of 10
o The Wildcat domain, a discrete structure within the T4, is steeply dipping to the east
and strikes for 237 m and terminates at the 40 fault.
o The T1 Zone, previously described in the 2023 Trixie MRE, has been incorporated into
the T4 Zone. The T1 Zone was previously an envelope on the contacts of both the 75 -
85 and T2 Zones. The T1 Zone had similar high-grade fissure zones as described in the
T4 Zone, that are constrained within the T4 envelope. Additional drilling in this area also
reduced the estimated contained gold above cut-off.
• The 75-85 Zone is a moderately west dipping silica sulphide cemented breccia zone. Drilling
along strike to the south suggests that the 75-85 Zone truncates both the T2 structure and T4
zone. Mine development in 2023 intersected previously unknown stopes within the modelled 75-
85 Zone and high-grade assays were less continuous at depth, although increasing down plunge.
Table 2: 2024 Trixie MRE Separated by Domain – March 14, 2024
Domain Category Tonnes Grade
(Au g/t)
Contained
Gold (oz)
Grade
(Ag g/t)
Contained
Silver (oz)
T2
Measured 22,678 106.27 77,484 115.99 84,572
Indicated 11,939 23.19 8,902 51.07 19,602
M+I 34,617 77.62 86,387 93.60 104,173
Inferred 1,996 9.82 630 61.38 3,938
T3
Measured 2,385 9.46 725 75.34 5,776
Indicated 970 5.47 171 57.32 1,787
M+I 3,355 8.30 896 70.13 7,564
Inferred 139 6.27 28 63.14 282
T4 +
Wild
Cat +
40 FLT
Measured 94,784 8.93 27,227 48.41 147,520
Indicated 51,827 6.48 10,795 37.59 62,637
M+I 146,611 8.07 38,023 44.58 210,156
Inferred 104,676 6.57 22,127 38.57 129,792
75-85
Measured - - -
Indicated 60,008 12.93 24,943 80.95 156,185
M+I 60,008 12.93 24,943 80.95 156,185
Inferred 94,793 9.12 27,784 59.28 180,666
Total
Measured 119,847 27.36 105,437 61.73 237,868
Indicated 124,743 11.17 44,811 59.89 240,211
M+I 244,590 19.11 150,248 60.80 478,078
Inferred 201,603 7.80 50,569 48.55 314,678
Refer to notes described under Table 1, which are also applicable to Table 2 in their entirety.
TRIXIE AND GREATER TINTIC CONCLUSIONS AND RECOMMENDATIONS
• In 2023, the Company completed a total of 6,028 m (19,776 ft) of underground drilling in 73
diamond drill holes at Trixie. Assays were finalized up to hole TRXU -DD-23-069 and were
included in the 2024 Trixie MRE.
• The new drilling, mapping and historical data compilation improved the interpretation and
revealed that there is significant potential for parallel high -grade gold fissure zones similar to
T2 and adjacent to the existing mine development. Much of the Trixie area remains unexplored.
• At Trixie, exploration potential remains highly prospective at depth near historical stopes that
ceased mining at the water table. The Trixie deposit remains open to the north, along strike of
Page 4 of 10
T2, down dip below the historical 756, down plunge to the Survey Vein and additional, parallel
structures are highly possible within the epithermal system.
• The Company continues to explore for additional high-sulphidation epithermal Au and Ag targets
along the 4 km strike length of historical mines and has identified at least a dozen new drill
ready targets from extensive data compilation and regional field work in 2023. Further work is
recommended to test these targets (see Figure 3 for property wide historical deposits and
exploration targets).
PORPHYRY TARGET DRILLING
• Copper-gold-molybdenum porphyry potential remains an exploration priority for the Company.
One diamond drill rig is currently active at surface testing a porphyry target at Big Hill and is at
a current depth of 1,180 m (3,872 ft). Assays are pending for this drillhole.
• One drill hole tested a copper-gold-porphyry target below Trixie and was drilled to a depth of
759.6 m (2,492 ft) when it crossed the Eureka Lily Fault to the east and out of the prospective
alteration zone. Further drill testing of a copper-gold porphyry target at depth below the Trixie
deposit is recommended to the west.
• The development of the 1,390 m decline ramp at Trixie, completed in September 2023,
significantly improving access to the underground workings for exploration development and
drilling beyond the 625 level.
• The Company has advanced rehabilitation at the 750 level to allow for further underground
diamond drilling to test for the down dip extent of the 756 zone and the porphyry target below
Trixie.
Page 5 of 10
Figure 1: Trixie geologic model and mineral domains cross section
Page 6 of 10
Figure 2: Exploration potential at Trixie
Page 7 of 10
Figure 3: Property wide mineralization and exploration targets
Table 3: Trixie MRE Cut-Off Grade ("COG") Sensitivity (Base Case in Bold) – March 14, 2024
Classification Tonnes COG Grade
(Au g/t)
Contained
Gold (oz)
Grade
(Ag g/t)
Contained
Silver (oz)
Measured +
Indicated
366,130 2.50 13.79 162,348 50.18 590,666
324,251 3.00 15.23 158,722 53.31 555,740
291,005 3.50 16.64 155,716 56.19 525,681
261,219 4.00 18.14 152,350 58.95 495,091
244,590 4.32 19.11 150,248 60.80 478,078
237,143 4.50 19.58 149,266 61.52 469,058
217,327 5.00 20.99 146,677 64.07 447,646
198,538 5.50 22.55 143,909 66.19 422,504
182,842 6.00 24.01 141,164 68.57 403,074
Page 8 of 10
165,955 6.50 25.81 137,734 71.39 380,902
152,986 7.00 27.55 135,503 74.34 365,663
Inferred
438,189 2.50 5.26 74,056 34.46 485,528
342,880 3.00 5.99 66,034 38.38 423,112
279,722 3.50 6.65 59,767 41.84 376,306
224,039 4.00 7.42 53,438 46.31 333,578
201,603 4.32 7.80 50,569 48.55 314,678
190,002 4.50 8.02 49,009 49.90 304,803
163,894 5.00 8.60 45,313 53.08 279,718
141,728 5.50 9.16 41,742 55.92 254,818
123,472 6.00 9.71 38,532 58.70 233,028
106,080 6.50 10.35 35,291 60.43 206,087
91,725 7.00 10.99 32,397 61.91 182,579
Note: Micon International Limited's QP has reviewed the COG used in the sensitivity analysis relating to the 2024 Trixie MRE and is
of the opinion that the individual cut -off grades used in the sensitivity analysis meet the test of reasonable prospects of economic
extraction. The numbers in bold represent the current 2024 Trixie MRE.
Table 4: Trixie MRE Cut-off Grade Calculation Breakdown
PARAMETERS VALUES
Mining Cost ($/ST) $74.33
G&A ($/ST) $52.71
Heap Leach ($/ST) $41.00
Total Refining Cost/ OZ $2.65
Gold Price $1,750
Royalty (Combination) 4.50%
Heap Leach Au Recovery 80.0%
Cut-off Grade (COG) 4.32
The cut-off grade for the 2024 Trixie MRE is 4.32 g/t Au compared to 4.85 g/t Au in the 2023 Trixie MRE
primarily due to the difference in the estimated cost of heap leach processing ($41/ST) relative to the
previously estimated mill processing scenario ($89/ST).
Qualified Persons
The scientific and technical information contained in this news release has been reviewed and approved
by Maggie Layman, P.Geo., Vice President, Exploration of Osisko Development, and a "qualified person"
within the meaning of NI 43-101.
The independent QPs for the 2024 Trixie MRE, within the meaning of NI 43-101, are William Lewis,
P.Geo. and Alan J. San Martin MAusIMM(CP) of Micon International Limited. Each QP is independent of
Osisko Development within the meaning of NI 43 -101 and has reviewed and approved the content in
this news release.
Quality Assurance (QA) – Quality Control (QC)
All drill core and exploration samples are dispatched to ALS Geochemistry or SGS Canada for offsite
sample preparation and analysis. Both labs are ISO/IEC 17025 certified, and ALS Geochemistry is also
ISO 9001 certified. Samples are assigned a unique sample ID. All geological and sampling information
is entered into a Datamine Fusion database. Core is sawn in half and half is sampled. Certified standards
and blanks are inserted into all sample dispatches. Samples are collected by Old Dominion
Transportation and dispatched to SGS Canada 's laboratory in Burnaby, British Columbia or ALS