Gold Fields of Shamva is the parent company of Shamva Mine - an underground mining operation.
Shamva Mine is located in Mashonaland-Central province, about 90 kilometres northeast of the capital city of Harare and some 29 kilometres east of Bindura.
Shamva Mine is situated in the Shamva greenstone belt and exploits numerous orebodies which occur within a 300- to 400-metre wide Riedel-type shear system. The sub-vertical orebodies are indistinguishable from the host rocks. Mineralisation within the orebodies consists predominantly of pyrite (>90%) with minor sphalerite, galena, chalcopyrite, pyrrhotite and arsenopyrite. Gold is found in contact with the sulphides, often in fractures, and varies significantly in grain size with visible gold commonly intersected in development and underground drilling. Silver occurs with the gold and represents some 50% of gold content.
Mining and processing
The Shamva Mine claims were first worked in 1893 on ancient workings along the summit of Lone Star Hill, the original name of Shamva Hill. Recorded production from 1909 to December 2015 yielded 2.38 million ounces of gold. The mine comprises two shafts, Shamva shaft for men and material and Cymric shaft for ore hoisting, from which ore is processed through a single metallurgical facility that uses a combination of crushing, conventional milling and combined gravity carbon-in-solution/carbon-in pulp process.
The current hoisting capacity is 45ktpm and current milling capacity is 33ktpm. The average mined grade is 2.90g/t.
Production for 2016 was 21,061 ounces, with C1 costs of $1,085 per ounce.
- Current resource: 2.5 million ounces of gold (Mineral Reserve Statement Dec 2016)
- Life-of-mine: 22 years
In 2016, the mine engaged the services of a contract mining company (Africa Mining and Exploration) to deliver at least 35000tpm of ore to the plant.
Shamva orebodies are open ended both on strike and exploration RC drilling is targeting new mineralised structures in close proximity to current mine workings.
In 1999, SRK scoped an open pit based on a resource of 19Mt at 1.7g/t gold at $360/oz gold price and low strip ratio of 3:1. This resource was re-stated by SRK as 6Mt at a higher 2g/t grade.
An RC drilling program with a total of 10,000m at an estimated cost of $1,000,000 is planned. The drilling will focus on eight targets on Shamva Hill and the Danton prospect located about 3km west of Shamva Mine, with the objective of fully testing mineralisation intersected by trench, diamond and RC drilling and projected from underground.
The objective of the planned surface exploration program is to generate near surface resources amenable to open pit mining to augment underground production and support the Shamva expansion program.
Ongoing refurbishment of the Processing Plant at Shamva Mine will expand capacity to 70,000 tonnes per month, increasing production.
The engagement of contract miners at Shamva Mine have yielded positive results and place the mine in a strong position to increase future output.