Buckreef Gold Project, Tanzania

The Buckreef gold project area comprises a dormant gold mine and four prospects located in the north-central region of Tanzania.

According to a joint venture agreement signed in October 2011, Tanzanian Gold (formerly Tanzanian Royalty Exploration) holds a 55% interest in the Buckreef gold project while the remaining 45% is owned by the Tanzanian State Mining Company (Stamico).

The gold project is expected to deliver an average gold production of 51,000oz a year and produce 822,000oz over its estimated mine life of 16 years.

Tanzanian Gold completed the first two phases of resource upgrade drilling in February 2020 along the 1.2km Buckreef shear zone. It announced 4.29Moz of gold contained in 242.4Mt grading at 0.57 g/t of Au at a block cut-off grade of 0.1g/t of Au.

The new sulphide processing plant will have the capacity to process up to 3Mtpa, according to the preliminary design criteria. It is expected to produce 150,000oz to 175,000oz of gold annually.

Development of Buckreef gold project

The Buckreef gold project was operated as an underground gold mine by the Tanzanian Government in the late 1980s. The rights over the mine were owned by Iamgold Tanzania until July 2009.

An agreement was signed between Iamgold and the Ministry for Energy and Minerals for the redevelopment of Buckreef gold project. It included 12 prospecting licences and a single special mining licence. The Commissioner for Minerals revoked all licence applications for the redevelopment project after Iamgold moved an application for the cancellation of the licences in July 2010. Tanzanian Gold was awarded the tender for the Buckreef project in December 2010.

Under the terms of the JV agreement signed with Stamico, Tanzanian Gold is responsible for the management of the project.

The special mining licence SML04/1992 was extended by ten years to June 2027 following a renewal.

Buckreef gold project location

The Buckreef gold project site is located 45km south-west of Geita district and immediately towards the south of Victoria Lake Goldfields in north-central Tanzania. It is situated 110km south-west of the city of Mwanza.

The project can be accessed by ferry from Mwanza across Smith’s Sound and Lake Victoria through Busisi or Kamanga, and via a sealed road through Geita. Alternatively, the site is accessible via a sealed road through Kahama and Shinyanga, followed by a gravel road north to Bulyanhulu before turning west to Nyarugusu.

Geology and mineralisation details

The project includes five gold deposits in a single special mining licence within the Buckreef mining area (BRMA) and the Buziba-Busolwa mining area (BZMA). The prospective licences cover 33.2km² while the special mining licence spans across 16.04km².

The deposits included in the project are the defunct Buckreef mine, Buziba, Bingwa, Eastern Porphyry and Tembo.

The Buziba and Buckreef deposits are orogenic gold deposits of medium-grade hosted by mafic volcanic sequences in the eastern portion of the Archaean Rwamagaza Greenstone Belt (RGB), which lies within the Tanzanian Craton.

The mineralisation at the Buziba prospect comprises quartz vein arrays present in altered shear zones in pillowed mafic rocks and as stockworks in the felsic porphyries. The prospect is located 20km to the east of the Buckreef deposit.

The Bukreef deposit is located in the central part of the Buckreef Project area. The prospect is hosted by 5-30m-wide and 8km-long, steeply dipping northeast-southwest trending brittle-ductile shear zone within relatively undeformed mafic volcanics.

Bingwa prospect is located approximately 4km east of Buckreef, at the northern margin of the RGB near a sheared contact with a granitic intrusive. Mineralisation within the deposit features quartz veining and altered greenstone in a shear zone that abuts the granitoid contact.

Situated less than 1km east of the Buckreef main deposit, the Eastern Porphyry prospect is characterised by weakly to moderately sheared felsic porphyry and feldspar quartz up to 30m-wide within a mafic sequence.

The Tembo deposit lies 3km south-west of the Buckreef deposit in sub-parallel shear zone towards the east-west trending main shear zone of Rwamagaza. The mineralisation of gold is associated with veinlets, boudins and grey quartz stringers constrained by east-west shears occurring in basaltic volcanic units.

Mineral reserves

The Buckreef gold mine was estimated to contain 19.2Mt of proven and probable mineral reserves grading at 1.54g/t of gold, as of June 2018. The resource estimate of the Buckreef shear zone was doubled to 40.99Mt grading at 1.73g/t with contained gold of 2.27Moz in March 2020.

Mining and processing at Buckreef gold project

An open-pit truck and excavator mining method is being considered for the Buckreef project due to the geometry of the ore bodies. The project will target high-grade oxide reserves at or near the surface. The use of trucks and loaders will deliver cost benefits and good selectivity.

The fleet will include 17 40t trucks and four backhoe excavators to haul waste and ore materials through the life of mine. The ore processing plant will include crushing, grinding, gravity and concentration stages, before the ore is treated by the carbon-in-leach (CIL) method on the gravity circuit. The design of the processing plant was prepared following extensive metallurgical test-work.

The ore processing plant will be able to operate at 60tph, which will be gradually increased to 180tph from the fourth year of operation.

The test work indicated that high recovery of gold is possible through the use of conventional comminution process, involving the latest EDS system instead of conventional ball and roller mill circuit, gravity concentrate, flotation and leaching circuit.

The Buckreef gold project is projected to produce 1.49Mtpa of ore over the life of the mine.

The processing plant will respectively have gold recoveries of 92.3% and 85% for primary oxides and sulphide ores.

Infrastructure at Buckreef gold project

The project includes a 110kV transformer sub-station, provincial roads, a Tanzania Telecom line and cell phone coverage by Vodacom, Airtel, Halotel and Tigo.

The infrastructure will include waste rock sites, a central ore milling and processing plant, tailings storage facilities, mine operation buildings, ore stockpile, office and housing spaces with on-site accommodation.

The project site also has access to a 1,000m gravel airstrip for emergency medical evacuation.

The existing infrastructure also includes a defunct vertical shaft, open-pit and waste rock dump, borehole for domestic water sources, waterlines, pumps,  inoperative heap leach pads, a 10tph carbon-in column processing plant, a 200tph crusher unit with scrubbers, as well as office and accommodation buildings.

The electrical power for the Buckreef mine site is supplied by Tanzania Electricity Supply Company (TANESCO) via a single transmission line.

Contractors involved

Virimai Projects was contracted to prepare the pre-feasibility study for the project. MaSS Resources was selected to prepare an independent optimised mine plan, in October 2016. It published the technical mining reserve estimate and economic feasibility study report in May 2017, which was later reviewed by Virimai.

SGS Canada is conducting metallurgical testing on the primary ore at its facilities in Ontario, Canada.

In May 2020, PricewaterhouseCoopers Corporate Finance (PwCCF) was selected to help secure financing for the Buckreef gold project.