Registered with the Ministry of Mines as Mining Lease No. 17, Freda Mine covers an 837 hectare area with numerous claims and 14 licensed mining blocks outside of the lease.
It is essential to undertake exploratory work to access new ore reserves. This is a full-time process requiring significant cash outflows to finance the expertise necessary to undertake the diamond drills and various other advanced evaluative techniques to prove ore reserves. As such the entity has to embark on exploratory work within the lease to extend the life of the mine. The aim therefore is to establish an exploration department or outsource to spearhead this task within this timeframe.
An extensive Life of Mine Planning (LOMP) exercise needs to be undertaken to identify mineral resources within our mining lease and modify them into ore reserves to extend the life of the mine. Such exploration is highly capital intensive and the combination of the current economic challenges in Zimbabwe mean access to the finance required for this exercise is either unavailable or too costly.
The Gurus has numerous satellite deposits within its mining lease. These deposits are the basis of the exploration function, which through a combination of internal and community-based projects as detailed below, are at the primary stages of quantification. Material from the satellite deposits is processed through the pilot plant, as part of metallurgical testing and to prevent distortion of the main plant recoveries. Free gold recoveries in this regard are above 75% suggesting that ores from these deposits can be fed into the existing plant.
Ore bodies generally comprise shear zones which are in-filled with gold bearing sulphides and quartz. Mineralised zones have average grades of 5 to 8g/t with approximately 35 - 50% of recoveries being free gold.
Activities include hard rock mining accessed through sublevel mining for free gold extraction through the various shafts within the 837-hectare mining lease. This is the primary extraction method accounting for ±60% of annual production.
Ores are accessed through traditional drill and blast techniques using jackhammers and hauling by way of cocopans, accounting for daily extraction targeted at ±100tonnes.
Due to the depletion of ore reserves, we have temporarily scaled down underground operations and are reprocessing waste material (sands). At this level we have the capacity to process ±500tonnes per day and are viable due to the significantly reduced overhead. Available waste material is limited as we have almost completely exhausted all surface material. We therefore intend to finance the LOMP exercise by ploughing back profits from current operations, however this automatically extends the timeframe significantly as we must first generate the funds required..
The crushing plant feed from underground is tipped through a surface grizzly and conveyed for reduction in a two-stage crushing operation in closed circuit with a vibrating sizing screen. The final crusher product at -10mm is conveyed into the mill feed silos for feeding into the primary mill.
The milling plant is designed to process ±100 tonnes of dry ore per day. It comprises a primary mill that is fed from the mill feed silos and a regrind mill that is fed from the sands. The products from the two mills is concentrated in two 3-4 tph Querl Bowl gravity concentrators connected in parallel for the two streams. The concentrator tails feed into a classifier mechanism from which the underflow feeds back into the regrind mill for further size reduction to 80% passing 75 micron sieve. The overflow from the cyclones pumps to the dewatering tank for density correction ideal for leaching and gold adsorption by activated carbon.
The dewatering cone underflow passes through a trommel screen for the removal of entrained trash and wood chips that would impact negatively on gold dissolution and adsorption. This also helps in the removal of excess size particles that would have otherwise surpassed the classification stage.
The trash screen undersize feeds into the 3-stage 40 m3 CIL circuit for the dissolution and adsorption of gold onto carbon. Carbon concentration is maintained at 20g/l in all the three contactor tanks. Cyanide and caustic soda are dissolved and added into the first tank.
A separate crushing unit consists of four three-stamp stamp-mills which are specifically reserved for the finer gold-bearing ores and serves as the pilot plant. This plant has 10% the capacity of the main crushing plant processing a maximum of 20 tonnes daily.
Developments to date
This was made possible by the following investments:
Assay Lab Metallurgical accounting is an essential feature of all efficient metallurgical operations. It is used to determine values contained in various process streams in the plant and it is also used to make decisions about the operation since the values of recovery and grade obtained from the accounting procedure are indications of process efficiency. This explains why Freda Assay Lab exists. The following is done in the lab:
Lab services are also available to surrounding mines at competitive prices.
Average operating capacity has been at 80% daily for the year since 2020, on processing surface material. Underground operating capacity has been limited to 20%, the major limiting factor being that the ore reserves have been depleted and we are effectively exploring new reserves.
We have ±3 000 000 tonnes of sands available for leach extraction. However, with the current plant design, we are unable to extract more value from these sands. Metallurgical test work is underway regarding the most efficient methods to extract the mineral from these dumps. Any ore reserves identified from the current life of mine planning exercise will further increase the tonnage for the dump for future extraction.
The ROM (run of mine) circuit has a crushing plant which comprises reduction of the ore in a two stage crushing operation in closed circuit, with a double deck vibrating screen. The feed to the crushing plant is tipped through a surface grizzly and then conveyed for reduction initially by a 10x21 Jaw Crusher (primary crusher) and lastly by a 24x5 Granulator (secondary crusher). The oversize product from both the crushers is recirculated for screening by the double deck vibrating screen with the top deck having aperture size of 24mm 2 and lower deck having aperture size of 16mm 2 . The final crusher product of -16mm is conveyed into the mill feed ore bin for feeding into the mill.
The milling plant is designed to process ±100 tonnes of dry ore per day through Mill 4. The mill product is concentrated by two Bowl concentrators and the concentrator tails will be fed to the hydrocyclones for classification through the use of a slurry discharge pump. Currently the cyclone overflow consolidates with the dump retreatment underflow, but ultimately a completely separate circuit incorporating a dewatering stage and a CIL circuit is the target which is still under construction.
The ultimate goal is to expand operations from current to large scale gold production. Through a combination of capital injections from new investors and ploughing back profits, the strategic goal is to expand operations to a capacity of ±1000 tonnes daily. This long-term goal will ensure that both the investors and the country will benefit from the operations of the mine by becoming a significant player in the gold production sector.
How to get there?
As with any venture, one of the most significant concerns is financing. As the viability of the project is not under any doubt, we strive to meet the financial requirements in the most cost-effective way. To date a combination of investor capital and ploughing back profits has led to present achievements. The drawback is that ploughed-back profits slow down the rate of growth as investment needs to be preceded by production. In light of this we are constantly on the look-out for viable alternative means of finance to catalyse the expansion effort.
