OKO WEST PROJECT
GUYANA
The Oko West Project
Reunion Gold’s Oko West Project is a new gold discovery in northwest Guyana. The Project is located south of the historical “Oko” gold district, some 95 km west of Georgetown and accessible by the Puruni laterite road and trails from the towns of Bartica and Itabali on the Mazaruni river (Figure 1).
The Oko West Project comprises a Prospecting License with an area of approximately 44 square kilometres (Figure 1 and 2) that is 100% held by Reunion’s Guyanese subsidiary.
In 2020, Reunion Gold’s geochemical survey, trenching, and initial drill program discovered and confirmed the presence of gold mineralization in shear zones along the contact between a greenstone belt assemblage and a granitoid unit on the east edge of the project area.
Since then, a total of 565 drill holes totalling 144,134.6 meters were included in the calculation of this MRE, comprised of 125,705.6 meters in 393 diamond drill holes and 18,429 meters in 172 reverse circulation drill holes. A total of 57 trenches totalling 6,538.5 meters were also included in the calculation.
Mineral Resources Estimate
In June 2023, after 22 months of resource definition drilling, the Company announced an initial Mineral Resource Estimate (“MRE”) containing 2.475 Moz of gold in Indicated resources grading 1.84 g/t Au and 1.762 Moz of gold in Inferred resources grading at 2.02 g/t.
In February 2024, the Company announced an updated MRE with a significant increase in both grades and contained gold within the overall MRE and a substantial initial underground Resource as shown in Table 1. (see NI 43-101 Technical Report Oko West Gold Project, Cuyuni-Mazaruni Mining Districts, dated effective February 26, 2024 (link to report).
Table 1 – Oko West Summary of Mineral Resource Estimate
Note: See notes to Table 1 under each of Table 2 and Table 3 for Underground and Open Pit MRE, respectively.
The total combined open pit and underground Resource reported in the 2024 MRE includes 4.3 million ounces (M oz) of gold (Au) in Indicated Resources contained within 64.6 million tonnes (Mt) grading 2.05 grams per tonne (g/t) Au, with an additional 1.6 M oz of gold in Inferred Resources, contained within 19.2 Mt grading 2.59 g/t Au.
Initial Underground Resource
The 2024 MRE update includes an initial constrained underground Resource for Oko West of 1.1 M ounces of gold in the Inferred Resource category, contained within 11.1 Mt at a grade of 3.12 g/t Au and an additional 29,000 ounces of gold in the Indicated category.
Table 2 – Oko West Underground MRE summary
Notes:
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The Mineral Resources described above have been prepared in accordance with the CIM Standards (Canadian Institute of Mining, Metallurgy and Petroleum, 2014) and follow Best Practices outlined by the CIM (2019).
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The Qualified Person (QP) for this Mineral Resource Estimate (MRE) is Pascal Delisle, P.Geo. of G Mining Services Inc.
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The effective date of the Mineral Resource Estimate is February 7, 2024.
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The cut-off grade used to report underground Mineral Resources is 1.38 g/t Au and a processing recovery of 92.5%.
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The Oko West Deposit has been classified as Indicated and Inferred Mineral Resources according to drill spacing. No Measured Mineral Resource has been estimated.
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The density has been applied based on measurements taken on drill core and assigned in the block model by weathering type and lithology.
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A minimum thickness of 3 meters and minimum grade of 0.30 g/t Au was used to guide the interpretation of the mineralized zones.
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This MRE is based on a subblock model with a main block size of 5 m x 5 m x 5 m, with subblocks of 2.5 m x 2.5 m x 2.5 m, and has been reported inside an optimized pit shell. Gold grades in fresh rock, transition and saprolite were interpolated with 1 m composites using Inverse Distance for domains AU_2A, AU_2B and AU_5, and Ordinary Kriging for all other domains. Capping was applied on eight domains, ranging from 5 g/t Au to 80 g/t.
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UG optimization parameters and cut-off grades assumptions are as follows:
i. Gold price of US$1,950/oz
ii. Total ore-based costs of US$73.26/t for fresh rock
iii. The Deswik.SO (DSO) was used to constrain the Resources
iv. Royalty rate of 8%
10. Tonnage has been expressed in the metric system, and gold metal content has been expressed in troy ounces.
The tonnages have been rounded to the nearest 1,000 tons, and the metal content has been rounded to the nearest 1,000 ounces. Totals may not add up due to rounding errors.
11. These Mineral Resources assume no mining dilution and losses.
12. These Mineral Resources are not mineral reserves as they have not demonstrated economic viability. The quantity and grade of reported Inferred Mineral Resources in this news release are uncertain in nature and there has been insufficient exploration to define these resources as indicated or measured; however, it is reasonably expected that the majority of Inferred Mineral Resources could be upgraded to Indicated Mineral Resources with continued exploration.
Open Pit Constrained Resource
The updated open pit constrained MRE by weathering category is shown in Table 3 and is also illustrated in Figures 3, 4 and 5. The open pit Resource was calculated to a depth of approximately 640 m (about 55 m below the pit bottom used in the June 2023 resource calculation) and is comprised of 4.2 million ounces of gold in the Indicated category contained within 64.1 million tonnes grading 2.06 g/t Au, plus an additional 488,000 ounces of gold in the Inferred category contained within 8.1 Mt grading 1.87 g/t. This represents a 71.2 % increase in the Indicated pit constrained resource from the initial MRE (see press release dated June 13, 2023) with an 11.7 % increase in grade. The increase in the pit constrained indicated ounces and grades reflects the trend towards increasing grades at depth in the Block 4 area of the Kairuni zone as illustrated in Figure 1. The reduction in inferred ounces from the June 2023 MRE reflects the high rate of conversion to an Indicated category resulting from the infill drilling program. Approximately 90 % of the total open pit Resources have now been converted to the Indicated category, with most of the remaining inferred ounces located within Blocks 5 and 6.
Table 3 – Oko West Open Pit Constrained MRE summary by weathering profile
Notes:
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The Mineral Resources described above have been prepared in accordance with the CIM Standards (Canadian Institute of Mining, Metallurgy and Petroleum, 2014) and follow Best Practices outlined by the CIM (2019).
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The Qualified Person (QP) for this Mineral Resource Estimate (MRE) is Pascal Delisle, P.Geo. of G Mining Services Inc.
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The effective date of the Mineral Resource Estimate is February 7, 2024.
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The lower cut-offs used to report open pit Mineral Resources is 0.30 g/t Au in saprolite and alluvium/colluvium, 0.313 g/t Au in transition, and 0.37 g/t Au in fresh rock.
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The Oko West Deposit has been classified as Indicated and Inferred Mineral Resources according to drill spacing. No Measured Mineral Resource has been estimated.
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The density has been applied based on measurements taken on drill core and assigned in the block model by weathering type and lithology.
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A minimum thickness of 3 meters and minimum grade of 0.30 g/t Au was used to guide the interpretation of the mineralized zones.
-
This MRE is based on a subblock model with a main block size of 5 m x 5 m x 5 m, with subblocks of 2.5 m x 0.5 m x 2.5 m, and has been reported inside an optimized pit shell. Gold grades in fresh rock, transition and saprolite were interpolated with 1 m composites using Inverse Distance for domains AU_2A, AU_2B and AU_5, and Ordinary Kriging for all other domains. Capping was applied on eight domains, ranging from 5 g/t Au to 80 g/t.
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Open pit optimization parameters and cut-off grades assumptions are as follows:
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Gold price of US$1,950/oz.
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Total ore-based costs of US$14.51/t for saprolite and alluvium/colluvium, with a 96% processing recovery US$17.16/t for transition with a 95% processing recovery and US$19.80/t for fresh rock based on 92.5% processing recovery.
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Inter-ramp angles of 30° in saprolite and alluvium/colluvium, 40° in transition and 50° in fresh rock.
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Royalty rate of 8%.
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Tonnage has been expressed in the metric system, and gold metal content has been expressed in troy ounces.
The tonnages have been rounded to the nearest 1,000 tons, and the metal content has been rounded to the nearest 1,000 ounces. Totals may not add up due to rounding errors.
15. These Mineral Resources assume no mining dilution and losses.
16. These Mineral Resources are not Mineral Reserves as they have not demonstrated economic viability. The quantity and grade of reported Inferred Mineral Resources in this news release are uncertain in nature and there has been insufficient exploration to define these resources as indicated or measured; however, it is reasonably expected that the majority of Inferred Mineral Resources could be upgraded to Indicated Mineral Resources with continued exploration.
Figure 1: Oko West Project location showing access roads and regional geology.
Figure 2: Oko West Project Prospecting License area outline with geology soil geochemical anomalies.
Figure 3: Inclined long section showing the updated MRE and resource classification across the resource in relation to the open pit and underground constraints.
Figure 4: Inclined long section showing the updated MRE in relation to open pit and underground constrained resources.
Figure 5: East-West Section along 701855mN (80m thickness, looking north) showing a slice through the open pit and underground constrained resources with continued mineralization down to depths of over 1,000m (1,100m downdip).
Geology and mineralization
The Oko West Project area is underlain by a greenstone belt assemblage of rocks from the Barama Group, consisting of mafic volcanics flows, volcanoclastic sediments and granitic plutons of the Proterozoic age. Reunion Gold has confirmed the discovery of a new gold deposit hosted in these units at the eastern edge of the project area.
The sequence hosting the bulk of the Oko West gold mineralization is composed of siliclastic, volcanoclastic, and carbonaceous sedimentary rocks. This assemblage ranges from 100m to 200 m thick and has an overall tabular shape, dipping steeply to the east and situated between a “hangingwall” granitoid pluton to the east and a “footwall” granitoid sill to the west. The sedimentary units are intercalated and strongly deformed; their spatial position is conditioned by their original deposition and polyphase folding.
Silica, carbonate, sericite, and sulphide alteration characterize the zones of gold mineralization. The mineralized intervals are generally associated with boxwork or stockwork veining composed of quartz/quartz-carbonate shear veins and multiple generations of extension veins.
Exploration program
In 2019, Reunion Gold launched its exploration program, including geological mapping, stream sediment geochemistry, and a detailed airborne magnetic and radiometric survey.
Geochemistry
In 2020, Reunion Gold performed a soil geochemical survey with samples taken every 50 m along lines spaced 200 m apart. The survey defined a gold-in-soil anomaly with a strike length of approximately 6 km. The anomalies coincide with shear zones associated with the geological contact between a sequence of volcano-sedimentary rocks and granitic plutons and sills.
Trenching
The Reunion Gold followed up the geochemical survey with a mechanized trenching program designed to test the geochemical anomalies at shallow depths. The trenching program consisted of excavator-dug trenches with channel samples collected from weathered rocks on the trench walls. Thirty-three trenches were excavated at approximately 200 m intervals over the northernmost 2 km of the gold soil geochemical anomaly (the Kairuni zone), totalling over 7,500 linear meters. table 1 report the assay results from these trenches. The trenching program confirmed that gold mineralization extends into the weathered bedrock (saprolite).
Drilling
On February 18, 2021, Reunion Gold reported assay results from the completion of its initial 1,000-meter diamond drilling program. These drill holes confirmed the down-dip continuity of gold mineralization to 100 m in the saprolite below trenches 4, 9, 18 and 19.
The encouraging results from the initial drill program prompted Reunion Gold to launch a robust drill program to systematically test gold mineralization’s vertical and lateral continuity along the 2 km long Kairuni zone. The drilling program was initially designed with east-west drill “fences” spaced every 100 meters. This program began on June 17, 2021, with one diamond drill rig, and on July 25, 2021, Reunion Gold added a reverse circulation drill. In October 2021, it added a second diamond drilling rig. In April and June 2022, a third and fourth more modern diamond drill rigs were added to close the spacing between drill holes to a 50 m grid spacing. Drilling has continued continuously since June 2021 and as of January 2023 the company was continuing to drill with 5 diamond drill rigs and 2 RC drill rigs. For a complete list of the results released to date please see the tables below. For up-to-date information on the drill program, including maps and figures please see the presentation on the website and the most recent press releases with updated drill results.
Tables 1-3 show detailed trench, diamond drilling, and reverse circulation drilling results can be found in the links below:
Link to: Table 1: Trenching results
Link to: Table 2: Diamond drilling composite results
Link to: Table 3: Reverse Circulation drill composite results
Additional exploration targets at Oko West
In addition to the resource definition drilling at Oko West, the Company has expanded its exploration program to the 3 targets outside of the Kairuni zone and in other areas of the Prospecting License (“PL”) (These targets areas are outlined in the Company’s corporate presentation and recent press releases). This includes commencement of a Scout RC Geochem program (“SRCGP”) in the western areas of the PL (Bryan zone), which represents a potential source area for historical alluvial gold mining that lies downstream and to the west of the project area Soil geochemistry was an important tool used in the discovery of the Kairuni zone, however in the western portion of the PL, a thick duricrust cover combined with alluvial material in drainages has limited the effectiveness of the initial wide spaced (400m lines) soil geochem program completed in 2020. The SRCGP was designed to address this by drilling 10 to 20 m deep RC holes to penetrate this leached cover material and sample the saprolite beneath. It appears from the initial results that the SRCGP is proving to be an effective tool in helping to identify areas of anomalous gold and therefore define additional drill targets on the Project. Initial results from the shallow Scout RC holes (with an average 12m depth) can be found in our most recent press release (which can be found on our website) and already demonstrate new target areas for planned follow up. This follow up program is expected to commence sometime by the end of the 2nd quarter 2023, using a combination of deeper RC and diamond drill holes.
Reunion Gold has also commenced a detailed ground magnetics survey over the Kairuni zone, to be followed up with a ground-based VLF survey. The program will then be extended south over the Takutu zone that represents the southern 4 km of the sheared granitoid/volcanic contact, and to the Carol zone target immediately adjacent to and west of the Kairuni zone. The program should help to identify the location of the favorable stratigraphic horizons and structures which the Company intends to proceed with a follow-up drilling program in the 2nd half of the year.
Tables 1-3 show detailed trench, diamond drilling, and reverse circulation drilling results can be found in the links below labelled table 1: Trenching results, table 2: Diamond drilling composite results, and table 3: Reverse Circulation drill composite results.
Link to: Table 1: Trenching results
Link to: Table 2: Diamond drilling composite results
Link to: Table 3: Reverse Circulation drill composite results
Notes to the tables of composite results
Composite drill and trench intersections calculations:
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Minimum composite grade of 0.3 g/t
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Minimum composite length of 2 m
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Cut off interval for inclusion is 0.3 g/t
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The maximum length of internal waste is 7 m
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Gold grades are uncapped.
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Mineralized intersection lengths are not necessarily true widths.
Sampling and analysis:
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Trench samples are channels taken horizontally and continuously in in-situ weathered rocks (saprolite) at regular intervals on trench walls. Reunion considers channel samples as sub-horizontal "drill holes" given their continuity and representative rock mass.
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Diamond drill samples consist of half of either HQ or NQ core taken continuously at regular intervals averaging 1.4 m, bagged, and labelled at the site core shed.
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Reverse circulation drill samples are obtained from a rotary splitter attached to a Metzke cyclone, weighed, bagged, and tagged at the drill site.
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Samples are shipped to the Actlabs certified laboratory in Georgetown, Guyana, respecting the best chain of custody practices. At the laboratory, samples are dried, crushed up to 80% passing 2 mm, riffle split (250 g), and pulverized to 95% passing 105 μm, including cleaner sand. 50 g of pulverized material is fire assayed by atomic absorption (AA). Initial assays with results above 3,000 ppb gold are re-assayed with a gravimetric finish. Certified reference materials and blanks are inserted at 5% of samples shipped to the laboratory. MSALabs, another certified laboratory in Georgetown, tests umpire samples generated by Actlabs.
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Assay data is subject to QA/QC using acQuire software and management by an independent consultant.
Other parameters:
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Drill and trench collar locations were surveyed by professional Guyana land surveyors using differential GPS and total stations.
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Diamond and reverse circulation drill holes are surveyed by down-hole equipment.
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Diamond drill core is oriented as frequently as possible.
