Environment & Climate Change

New Roasting Plant set to open in Kwekwe


Kwekwe and Zimbabwe at large would soon benefit, from the construction of a Kwekwe Polymetallic Ore and Concentrate Refinery (KPCR) plant to process and refine a wide variety of refractory gold ores and base metal concentrates which is on the cards.

The massive project valued at $89 million, was designed by BioMetallurgical Corporation (BioMet) a Zimbabwean engineering and technology company on behalf of Kwekwe Consolidated Gold Mines (KCGM). The plant will be set up at Bell Riverlea Mine along old Gokwe road.

Chat Reporter Online has it on good authority that a pre-feasibility study has been conducted and full implementation is simply awaiting funding.

In an exclusive interview with Chat Reporter Online recently in Kwekwe, BioMet’s Managing Director, Lee W John, said the project would be constructed in four phases to spread the capital expense, beginning with the setting up of a refractory gold processing facility with arsenic recovery in the first phase this year and a base metal refinery and roaster in phase two in 2019 which would also include a sulphuric acid recovery plant.

In phase three in 2020, the company would build an antimony refinery and other base metal by products refinery and finally in phase four in 2021, throughput would be increased and additional base metal processing and refining facilities would be established.

The BioMet managing director said the establishment of a roasting plant in Kwekwe would create around 500 permanent jobs on site at KPCR which would benefit the Kwekwe, Zhombe, Silobela, Gokwe, Kadoma and Gweru regions.

John said, “The empowerment of more than 40 medium scale and 500 small-scale mining syndicates in Zimbabwe would result in an estimated 15,000 jobs directly and another 50,000 jobs indirectly, benefiting our country substantially with considerable exports being generated to benefit the Zimbabwean economy.

“The KPCR will utilise a range of synergistic technologies that include pyrometallurgical and hydrometallurgical processing of ores and concentrates. For example, the sulphur dioxide produced from roasting of refractory gold concentrates and the smelting of base metal sulphides will be converted to sulphuric acid and used to leach base metal oxides and roaster calcine’s. Sulphuric acid will also be used to agglomerate low grade gold refractory gold concentrates that will be bio-leached prior to CIP gold recovery. Excess sulphuric acid will be sold as a by-product”.

John added that the base metal refinery will utilise Solvent Extraction Electro Winning (SXEW) technologies to produce pure copper cathode and a range of base metals.

“Products of the KPCR will include gold and silver bullion, copper cathode, arsenic oxide, antimony metal, nickel salts, cobalt salts, zinc oxide and a PGM concentrate. The actual production figures are subject to SMS mines and larger mines re-opening and producing concentrates but production will also come from BioMet mines including the Bell Riverlea Mine. The mines, skills and resources are present in Zimbabwe and such capacity to produce exists if provided with the capital required to develop such,” he said.

The managing director added that the setting up of such a facility would bring numerous benefits for SMS miners in that they will be paid quickly and preferably the same day as delivery of the ore or concentrate (provided it is delivered before 09:00hrs).

He added that BioMetallurgical had proposed a facility capable of meeting all these criteria.

The BioMet managing director told this publication that the country needs a new roasting plant.

He said, “Zambia has seen dynamic growth in the past 15 years due to proactive investment policies and a commodity price boom. Zimbabwe could achieve an even greater mining project boom with the total investment in Zimbabwe mining over the next ten years being more than what Zambia has achieved in the past ten years. The reason for this is that Zimbabwe has, fundamentally, a superior Mines and Minerals Act, supported by the Chief and Regional Mining Commissioners and a better education system and skills base than most other countries in Africa. Zimbabwe does not have the richest resources in Africa but it however, has had more historical mines (per square km) than any other country in Africa. This is due to the Mines and Minerals Act which allowed small, medium and large scale miners to prosper. In fact, the emphasis in the past was on a range of assistance provided to the small scale miners via the regional Mining Commissioners.

“Most other African countries do not support small-scale mining and this is why those countries have only illegal artisanal miners and a few large mines, if any”.

John added that SMS mining has the potential to employ and benefit, directly and indirectly by far, many more people than large-scale mining.

“It is for this reason that it should be promoted as soon as possible as SMS mining can have a much more positive impact on empowerment of local people and on the national economy.

“SMS miners often lack the scale of operation to justify a pyrometallurgical and/or hydrometallurgical process to treat the concentrates they produce. SMS miners will often only be able to justify the CAPEX for a simple mineral processing plant such as gravity or flotation concentrator.”

“Such plants may even lack Cleaner and Re-Cleaner circuits and thus those concentrates will be often low grade and thus unsuitable for export. Even where high grade concentrates are produced the small quantities do not allow for export as foreign buyers insist on 100 tonnes lots and regular supply etc”.

However, John was quick to point out that export of any concentrates is not ideal and if there are facilities to process such within Zimbabwe then the value adding should take place in Kwekwe.

He said, “Regardless of whether an SMS miner produces a low or high grade, base or precious mineral concentrate, refractory or not, they need to be able to generate cash quickly to sustain and build their operations.”

“Thus a facility to process and refine a wide range of base and precious metal concentrates is one of the things needed for SMS mining to prosper in Zimbabwe. The Roasting Plant Corporation facility in Kwekwe (which closed in the late 90’s) did buy concentrates from SMS miners but was limited to the processing of refractory gold ores viz: arsenopyrite and stibnite concentrates.”

“The payment terms of 3 months or more from the Roasting Plant Corporation also stressed the cash flow of SMS miners to the extent than many of them closed down in the nineties including the Bell Riverlea Mine (closed 1997).”

“To promote a wide range of SMS mining, SMS miners need to be able to toll process or sell their concentrates and be paid promptly. Also needed is the facility to process and refine a wide range of base and precious mineral concentrates produced by SMS miners including concentrates such as: base mineral concentrates – oxide and sulphide among them copper oxide (malachite) hand cobbed ore or gravity concentrates from the Kadoma (Copper Pot), Nkayi (Nkayi Copper), Kwekwe (Rifle Range), Chiredzi (Edward) and Masvingo regions; Polymetallic (Cu, Zn, Co, Pb, Au, Ag etc) sulphide concentrates from Gokwe (Copper King/Queen), Kwekwe (Cactus) regions among them, copper sulphide (chalcopyrite) concentrates from Kadoma (Copper Duke), Makonde, Mutare (Odzi Copper), Bikita (Umkondo) regions, copper and or nickel sulphide concentrates from Zhombe (Empress), Chegutu (Perseverance) regions and gold concentrates of all descriptions including refractory concentrates.

John gave examples among them, arsenopyrite refractory gold concentrates from Kwekwe (Club, Black Prince, Venus), Mutare (Cairndhu, Champion), Gwanda (Champion), Shurugwi (Belvedere) regions; stibnite refractory gold concentrates from Silobela (Gothic), Belingwe (Belingwe Star), Kwekwe (dozens of small workings) and Kadoma regions; low grade (20gpt) contaminated concentrates (flotation cleaner tails, combined with copper as produced by some gold mines etc) that cannot be treated by conventional means; and base or precious mineral, high grade ores that may have been hand sorted.

He outlined the advantages of situating the KPCR at the Bell Riverlea Mine among them the location of this inherently hazardous process (Arsenic containing refractory concentrates) well away from any built up area.

He noted the on-site use of the sulphur dioxide produced from roasting and smelting at the KPCR, for the leaching of oxide ores adding that previously at the roasting plant in Kwekwe the sulphur dioxide was emitted into the atmosphere.

“On-site acid production would also considerably reduce the required imports of Sulphuric acid from South Africa which would be a welcome import substitution in addition to the refined copper being sold locally and rest of the products being exported for dearly needed FOREX.”.

“The location is central Zimbabwe and has access via good tar roads from all parts of the country. A significant portion of Zimbabwe’s deposits of refractory gold and polymetallic sulphides, mostly owned by small scale miners, are located within a 200km radius of the proposed site”.

In phase one and two, 30 to 60 kg of gold per month are projected to be produced while in phase three and four this would reach 80 to 150 kg per month, 300 tonnes of copper LME grade A are expected to be produced per month in phase one increasing to 500 tonnes per month in phase four.

30 tonnes of arsenic trioxide per month would likewise be produced in phase one and in phase two 150 tonnes per month. Lastly 20 tonnes of antimony HG metal per month would be realised in the first phase and around 100 tonnes per month in the final phase.

John said that one of the fundamental principles that KPCR will operate under, will be spear headed by the implementation of the quick payment system and the provision of technical assistance to the SMS miners.

“Quick payment to sellers of ores and concentrates will be implemented as follows; Payment of 80% of first estimate on the same day as delivery and the corrected remainder within 3 days. This practice is vital for the SMS mining industry to restore production to the levels seen during the 1950’s to 1990’s. Delayed payments of up to 3 months by previous operators of the Roasting Plant resulted in a downward spiral of production as the miners battled with cash flows and lived hand to mouth.

“As the ore or concentrate is delivered the mass is determined via weigh bridge, the ore or concentrate is off loaded and fed through a crusher and an automatic sampler takes a representative sample under the witness of the seller (ore representative). The sample is riffled and split into six samples all of which are all sealed under the witness of the seller.

“The seller keeps one sample for umpire assaying if there is an argument over the assay. One sample is immediately sent to the lab where, using XRF spectrometry, an assay result is produced within an hour. Gold results are produced quickly by aqua regia digest and AAS. These figures are passed on to the accounts department and a cheque is produced for 80% of the estimated metal content based on the prevailing rates for that week. The SMS miner leaves with his or her proof of payment the same day!

“Once triplicate fire assays and base metal assays have been performed within the next three days, a revised metal content is calculated for the concentrate delivered. The remainder of the payment is then made via transfer to the SMS miner’s bank account.

“It must be stressed that lower grade concentrates incur higher processing costs and thus high grade concentrates will always achieve a better price per contained unit of metal. For interest sake; the old Kwekwe Roasting Corporation paid 77% of gold content to the SMS miners but only after about 3 months.

He concluded, “The provision of technical assistance to SMS miners is a fundamental philosophy of the planned KPCR project. Technical services and assistance in the fields of environmental, safety, survey, mining, geology, metallurgy, administration and training will be provided by the KPCR to the SMS miners.

“Services provided will be subsidised relative to delivered production and SMS miners will be ranked in Class depending on the quantity, quality and regularity of deliveries to the KPCR. Higher ranked SMS miners may qualify to receive subsidised hire of mining equipment and loans to expand their operations”.


Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button