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Oko West Project Guyana



OKO WEST PROJECT (100%-owned)


Reunion Gold’s Oko West Project is a brand-new gold discovery in northwest Guyana located south of the historical “Oko” gold district. 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. The mineralization coincides with the northern portion of a six-kilometre-long gold-in-soil geochemical anomaly. This northern 2 km of that geochemical anomaly, where most of the drilling has taken place, is referred to as the Kairuni zone. The southern 4 km of that geochemical anomaly (called the Takutu zone) has so far been tested with preliminary, wide-spaced (800m+) fences of RC drilling and represents one of several priority exploration targets on the project. The focused drill program at the Kairuni zone has confirmed gold mineralization in the saprolite and un-weathered rock, showing strong continuity of grades between holes. The current drilling is focused on a resource definition drill program to a depth of of approx 600 m, with the aim of delivering a maiden resource estimate (MRE) by mid-year 2023. The Kairuni zone remains open along strike and at depth. 



The Oko West Project is in the Cuyuni Mining 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 Puruni road leads to the Toroparu mine and is currently being rehabilitated.

Mineral rights

The Oko West Project comprises a Prospecting License with an area of approximately 44 square kilometres  (Figure 1 and 2) and is 100% held by Reunion’s Guyanese subsidiary.

Mineral Resources Estimate

On June 13, 2023, Reunion Gold announced an initial Mineral Resource Estimate (MRE) at the Kairuni zone on its Oko West Project. The pit constrained MRE is comprised of 2.475 million ounces of gold in Indicated Mineral Resources contained within 41.789 million tonnes grading 1.84 g/t, and 1.762 million ounces of gold in Inferred Mineral Resources contained within 27.129 million tonnes grading 2.02 g/t Au. Table 1 shows a breakdown of the MRE by tonnage, grade and total ounces (oz) of gold (Au), categorized by resource classification category. 

Table 1 – Oko West Mineral Resource Estimate by classification



  1. 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).

  2. The Qualified Person (QP) for this Mineral Resource Estimate (MRE) is Christian Beaulieu, P.Geo., consultant for G Mining Services Inc. 

  3. The effective date of the Mineral Resource Estimate is June 1, 2023.

  4. The lower cut-offs used to report open pit Mineral Resources is 0.30 g/t Au in saprolite and alluvium/colluvium, 0.33 g/t Au in transition, and 0.38 g/t Au in fresh rock.

  5. The Oko West Deposit has been classified as Indicated and Inferred Mineral Resources according to drill spacing. No Measured Mineral Resource has been estimated.

  6. The density has been applied based on measurements taken on drill core and assigned in the block model by weathering type and lithology.

  7. A minimum thickness of 3 meters and minimum grade of 0.30 g/t Au was used when interpreting the mineralized zones.

  8. 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 2 m composites using Ordinary Kriging. Capping was applied on six domains, ranging from 5 g/t Au to 40 g/t. 

  9. Open pit optimization parameters and cut-off grades assumptions are as follows:

i.    Gold price of US$1,800/oz, 
ii.    Total ore-based costs of US$14.67/t for saprolite and alluvium/colluvium, US$15.75/t for transition and US$17.94/t for fresh rock,
iii.    Inter-ramp angles of 30° in saprolite and alluvium/colluvium, 40° in transition and 50° in fresh rock.
iv.    Royalty rate of 8% payable to the Government of Guyana.

  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 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.

See the Company’s technical report titled “NI 43-101 Technical Report Oko West Gold Project Cuyuni-Mazaruni Mining Districts, Guyana” with an effective date of June 1, 2023 for additional information regarding this MRE, including key assumptions, parameters and methods used to estimate this resource, and known legal, political, and environmental risks that could affect the development of this resource. The report was prepared by Christian Beaulieu, P. Geo., consultant for G Mining Services Inc., and Neil Lincoln, P.Eng., VP Metallurgy for G Mining Services Inc.

Link to : NI 43-101 Technical Report

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 (Figure 1). Reunion Gold has confirmed the discovery of a new gold deposit hosted in these units at the eastern edge of the project area  (Figure 2).  

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 (Figures 2 and 5). 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.


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   (Figures 2 and 3).


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.   Figure 4 and table 1 report the assay results from these trenches. The trenching program confirmed that gold mineralization extends into the weathered bedrock (saprolite).


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.

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 2: Oko West Project area outline and geology showing soil geochemical anomaly.

Figure 3: Detail of soil geochemical anomalies divided into the Kairuni and Takutu zones.

Figure 3: Detail of soil geochemical anomaly divided into the Kairuni and Takutu zones.

Figure 4: Map of soil geochemical anomalies and highlighted trench results in Kairuni zone.

Figure 4: Map of soil geochemical anomalies and highlighted trench results.

Figure 5: Typical cross section through block 4 of the Kairuni zone looking west

Figure 5.png

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:

  • Minimum composite grade of 0.3 g/t    

  • Minimum composite length of 2 m 

  • Cut off interval for inclusion is 0.3 g/t 

  • The maximum length of internal waste is 7 m   

  • Gold grades are uncapped.   

  • Mineralized intersection lengths are not necessarily true widths.

Sampling and analysis:


  • 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.

  • 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. 

  • Reverse circulation drill samples are obtained from a rotary splitter attached to a Metzke cyclone, weighed, bagged, and tagged at the drill site. 

  • 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.

  • Assay data is subject to QA/QC using acQuire software and management by an independent consultant.

Other parameters:


  • Drill and trench collar locations were surveyed by professional Guyana land surveyors using differential GPS and total stations.  

  • Diamond and reverse circulation drill holes are surveyed by down-hole equipment. 

  • Diamond drill core is oriented as frequently as possible.


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