The Twin Hills Gold Project is located within Namibia’s prospective Damara Orogenic Belt, in proximity to and along strike of the producing, open-pit Navachab and Otjikoto gold mines.

Twin Hills is a sedimentary-hosted, structurally controlled gold deposit that fits the broad orogenic lode gold model and is amenable to conventional open-pit gold mining and carbon-in-leach metallurgical processing.

In June 2023 a Definitive Feasibility Study (“DFS”) was prepared by Lycopodium Minerals Canada (“Lycopodium”) in accordance with National Instrument 43-101—Standards of Disclosure for Mineral Projects (“NI 43-101”) and contemplates a low-risk, technically simple open-pit mine utilizing contract mining and feeding a conventional carbon-in-leach (“CIL”) metallurgical plant processing 5 million tonnes of mineralized material per annum.

Project Location

The Twin Hills Gold Project (the “Project”) is located in central Namibia approximately 150 km northwest of the capital city of Namibia, Windhoek and is owned by Osino Resources Corp. (“Osino”) through a number of its local subsidiary companies. The Project is comprised of 11 exclusive prospecting licenses (“EPLs”) granted by the government of Namibia, which are held over a combined area of 153,206 ha in and around the regional towns and settlements of Usakos, Karibib, Omaruru, and Wilhelmstal in the Erongo Region of Namibia as shown in the figure below.

Twin Hills Discovery History

The Twin Hills Gold Project lies within the Kuiseb Formation, a sequence of turbiditic marine sediments several kilometres thick, which was folded during the neo-Proterozoic Damara orogen between 520 and 500 Ma. The gold mineralization is hosted within a meta-greywacke unit, which has been tightly folded into an overturned syncline, underlain by biotite schist and cordierite schist.

The discovery and growth of Osino’s flagship Twin Hills gold deposit in 2019 is a telling story of hard work, perseverance and not following accepted dogmas regarding prescriptive geological models. It demonstrates the use of innovative sampling techniques to enhance the identification of targets for follow-up drilling. 

Between 2016 and 2017 David Underwood and Jon Andrew, Osino’ founding pair of exploration geologists, undertook a review of Osino’s exploration strategy which resulted in shifting Osino’s focus away from the known small deposit scale prospects to potentially much larger,  district-scale prospects by exploration targeting using fundamentals of orogenic gold deposits. The key regional features/criteria of the orogenic gold model, and how they relate to the Namibian and Damara Orogenic Belt setting, are as follows:

•     Very large, long-lived fault structures e.g. those found within the Omaruru and Otjohorongo Lineaments and the recently identified Karibib Fault;

•     Large sedimentary and volcanic basins as a source of fluids;

•     Compressional tectonics, which are required for pumping the fluids out of the basins and through these large 1^st order structures;

•     Zones of structural and lithological complexity along 2^nd and 3^rd order structures acting as trap sites for metal enriched hydrothermal fluids.

•     Multiple associated gold occurrences across the target.

This review entailed a re-interpretation of the regional structural framework and identification of prospective structures and potential traps under cover, initially using the public domain, high-quality government magnetic dataset. This resulted in the identification of the regional-scale Karibib Fault Zone and an early recognition of its large-scale mineralising system potential and the vectors that ultimately lead to the discovery of the Twin Hills gold system through thick cover.  

Mineral Resources

The maiden drill program consisted of 7 diamond drill holes located along 3 fence lines about 400m apart with 100m hole spacing. The program was designed to test bedrock gold anomalies covered by a thick layer of calcrete which were with a large magnetic and soil & calcrete anomaly which had been delineated earlier in 2019. 

This initial drill program was a resounding success with 5 of the 7 holes intersecting significant mineralization open in all directions. 

The best gold intercepts from Phase 1 included:

• 104m @ 0.70 g/t Au (from 115m), incl. 10m @ 1.27 g/t and 20m @ 1.11 g/t
• 189m @ 0.69 g/t Au (from 21m), incl. 14m @ 1.14g/t, 7m @ 1.42g/t and 5m @ 1.43g/t
• 78m @ 0.64 g/t Au (from 91m) incl. 23m @ 1.01g/t
• 65m @ 1.37 g/t Au (16 – 81m), incl. 31m @ 2.2g/t (42-73m)
• 17m @ 2.17g/t Au (116 – 133m), 11m @ 1.76g/t Au (165 – 176m), 6m @ 1.29g/t Au (182 – 188m), 7m @ 1.10g/t Au (16 – 23m) and 3m @ 2.73g/t Au (87 – 90m)

In July 2023, a request for proposal was issued to selected mining, process plant and infrastructure design and construction companies for front end engineering design (FEED) packages. Updated capital and operating cost estimates as well as an enhanced project implementation schedule were generated by December 2023, with some FEED close out activities then continuing into Q1 of 2024.

The objectives of the FEED packages were:

• to enhance and increase confidence in the DFS designs, cost estimates and forecast project implementation across all aspects of the Project, and
• to identify, quantify and prioritise supporting operational readiness tasks needing to be completed by Osino in parallel with the Project development activities.

 

Major elements included in the FEED packages were:

• Grade control drilling initiated for the first six months of planned production
• Geotechnical stability investigations completed for the Process Plant, Pit, PV Plant and Tailings Storage Facility (TSF)
• Geochemical investigations of tailings and waste rock dumps completed
• Alternative mining, stockpiling and processing schedules as well as access ramp designs prepared
• Contract mining scope increased, new requests for proposal issued and evaluated, including the mining services infrastructure and equipment
• Additional arsenic removal, tailings filtration, bulk density and flowability tests initiated
• Process engineering basic engineering designs including preliminary piping and instrumentation diagrams (P&ODs) completed
• TSF deposition and filtered stacking and compaction designs and cost estimated updated and enhanced to FEED standard
• DFS capital and operating cost estimates reviewed, upgraded to include all FEED design developments and basis of estimate prepared
• Integrated master schedule for the project prepared, with a basis of schedule document
• Project definition rating index (PRDI) prepared
• Process Plant and overall project execution plans (PEPs) prepared
• Site layout updated to include all of the latest developments
• Multiwell pump tests, water supply modelling, piping reticulation designs and abstraction permit applications completed for bulk water supply on site from boreholes
• Geotechnical investigations. borehole pump tests and preliminary water supply modelling and pipeline routing prepared for the Kranzberg aquifer and Khan River water scheme, as potential water supply backup for Twin Hills
• Okawayo river diversion and general stormwater management designs and cost estimates updated
• Continued detailed design of the 66kV bulk power supply line and steady interaction with NamPower concerning bulk power supply
• Enhancement of scope of work, issue of enquiries and evaluation of offers to supply about 37% of required electrical power from a photovoltaic (PV) plant to be operated by an Independent Power Producer (IPP)
• Continued activity to apply for and obtain various environmental and secondary permits needed before project implementation can commence
• Finalisation of Operational Readiness plan and detailed schedule.

 

Mineral Resource Statement

The mineral resource is that material within the reporting pit shell above a 0.3g/t Au cut-off grade. The mineral resource estimate (“MRE”) has an effective date of March 15, 2023 (see table), and corresponds to the DFS published by Lycopodium. The Company has filed the DFS report on SEDAR under its profile at www.sedar.com.

Notes on mineral resource reporting:

1. Figures have been rounded to the appropriate level of precision for the reporting of mineral resources.
2. Mineral resources are stated as in situ dry tonnes. All figures are in metric tonnes.
3. The mineral resource has been classified under the guidelines of the CIM Definition Standards for Mineral Resources and Mineral Reserves and adopted by the CIM Council, and procedures for classifying the reported mineral resources were undertaken within the context of the Canadian Securities Administrators NI 43-101.
4. The mineral resource is reported within a conceptual pit shell determined using a gold price of US$1,800/oz and conceptual parameters and costs to support assumptions relating to reasonable prospects for eventual economic extraction:
   a.     4% royalty (3% government royalty and 1% export levy)

   b.     Selling costs of US$2.75/oz
   c.     Mining costs of US$2.00/t ore and US$1.85/t waste, with additional cost attributed to depth below surface
   d.     Processing and rehandling costs of US$8.15/t run of mine ore
   e.     G&A cost of US$4.00/t run of mine ore
   f.      Slope angle of 48° in weathered rock and 55° in fresh rock
   g.     90% gold recovery from CIL circuit

5. Mineral resources that are not Mineral Reserves do not have demonstrated economic viability.

 

DFS Overview and Financial Analysis

The DFS was prepared in June of 2023 by Lycopodium Minerals Canada in accordance with National Instrument 43-101—Standards of Disclosure for Mineral Projects (“NI 43-101”).

The table below summarizes the results and key valuation metrics of the DFS on a pre- and post-tax basis.

The financial model was completed on a 100% project basis and includes a 3% gross royalty and 1% export levy to the Namibian government. The economic analysis carried out for the Project uses a cash flow model at a base gold price of US$1,750/oz and a 5% discount rate.

A sensitivity analysis utilising a range of gold prices and operating variables was completed.

Mine Design and Production Schedule

Inferred resources were excluded from the pit optimisation runs and the Reserve statement and were classified as waste during the LOM production schedule runs. The deposit is a large, shallow gold deposit that is amenable to bulk open pit mining.

Figure 2: Design, Layout and Location of Process Plant, Pit and Waste Rock Dumps

The project is planned as a multi-pit mining operation, as shown in Figure 2, with seven pushbacks in the Twin Hills Central / Bulge pit design and three separate satellite pits (Clouds, Clouds West and Twin Hills West) to be mined in different phases throughout the LOM. The pit design and scheduling has been undertaken to allow for interim pushbacks which will be mined early, thereby allowing higher grade to the plant to be maximised in the early years, and waste stripping deferred as far as possible into the future.

Plant Mineral Processing

The Twin Hills process plant will have a nameplate capacity of 5.0 Mtpa of ore and a nominal capacity of ~650 tonnes per hour (tph).

Gold recovery will be achieved using a 3-stage crushing, ball milling, gravity, pre-oxidation, carbon-in-leach (“CIL”), cyanide detoxification and tailings thickening and filtration process plant flowsheet. The process is based on conventional unit operations well proven in the industry and will achieve high recoveries from all major rock types that are planned to be processed.

The detailed plant flow diagram is depicted in the Figure below.

Site Location and Infrastructure

The Twin Hills Project is in central Namibia approximately 20 km from the local town of Karibib, and 150 km from the capital city, Windhoek. The Project area has access to excellent infrastructure by being in close proximity to Namibia’s well-maintained national rail, road and bulk utilities network.

The Project is located within 5km of the sealed national highway network, within 20 km of a major high tension overhead power line and within 220 km of the modern seaport of Walvis Bay, to the west of the Project, which is the main logistical port supplying the mining industry in the region. The Project is also within 30 km of the well-established Navachab gold mine, which has been in consistent production since 1989.

Proposed Project Development Plan

Osino’s intention is to continue to fast-track the development of the Twin Hills Gold Project. The Company is well into the Front-End Engineering and Design (FEED) phase of the project and has attracted international accquisition offers. Construction is expected to commence in H2 2024.