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How miners are losing gold during elution

By Mining Reporter – Wednesday 29 April 2020

HARARE – (Mining Index) – ARTISANAL and Small-scale Miners (ASM) are losing a significant amount of gold to boiler attendants during elution.

While gold leakages have mostly been linked to smuggling and selling of the yellow metal by ASM to unlicensed gold barons, at least a third of gold is projected to be lost through various loopholes that happen from the mining, milling, cyanidination, elution before the actual selling of gold.

A survey conducted by Mining Index reveals shocking findings of theft that happens during milling, with millers encouraging the owner of the ore to be present and monitor the milling process.

Small-scale miners who spoke to this publication say some millers refuse to remove dies from stamp mills, yet they know some refractory gold is left clinging on the liners.

“Miners must inspect motorbox before milling commence for any hideous openings or cavities and demand that these are sealed by switch welding,” said a gold miner based in Shamva.

Liners are welded inside to protect and prolong life of the motor box. At the end of milling process, dies are removed to allow thorough cleaning and flashing using hosepipes to dislodge any trappings in the motor box.

Most miners are losing money by doing custom milling and not further processing their tailings through cyanidination, a process in which all the locked up gold is beneficiated or further processed.

Miners say during the cyanidination process, carbon may also be stolen.

Miners say they have lost, and are losing a significant amount of gold to boiler attendants during elution. They note that at elution plant, a whole wire wool maybe stolen.

“Elution plant employees may put their own small wire wool which they will take when they open the boiler,”

“You should check the wire wool tray and inspect the wire wool before boiler is switched on and be physically present when it is switched off. Small pieces of wool wire should never be placed in the wire wool tray,”

“The elution process requires three sets of keys necessary before loading the ore. When opening the boiler, all parties including the miner, Fidelity Printers and Refiners (FPR) and the Zimbabwe Republic Police (ZRP) CID Unit responsible for monitoring minerals and fauna must be present,” said a small scale miner operating in Bindura.

He said these parties must be present when the wire wool is installed then lock their keys. Similarly, all parties must unlock their keys first and be present when wire wool is removed.

While miners admit the presence of FPR and CID unit representatives at the boilers during elution, they say stealing of gold by boiler attendants happens as FPR staff is sometimes overwhelmed and seldom climb up the boiler to check.

Efforts to get a comment from FPR’s General Manager Fradreck Kunaka were fruitless, as he had not responded to questions on how gold is stolen during elution despite the mandatory presence of Fidelity representatives during the milling process.

While the solution left after elution may contain some gold, some miners ignorantly choose not to witness the removal of carbons from boiler.

“On water washers, most miners leave the water with the boiler attendants, who then get the opportunity to redo the solution and obtain left-over gold,”

“Predictions are that boiler attendant can obtain at least 10g of gold from discarded water,” cautioned another small-scale miner based in Kadoma.

A mining professional in the gold sector predicted that miners obtain two-thirds of their gold after the elution process, losing out a third of their gold to boiler attendants.

He said 40-45 percent of gold is retained in the tailings, which boiler attendants further process and get more revenue.

“The miner only retains about 60 percent of their gold after milling. The rest can only be obtained through a process called cyanidination where the fine gold that is difficult to wheedle out during proper milling is extracted. Generally a mill owner makes more money than a miner. That’s why you find the experienced boiler attendants establishing their own mills and dumps,” said the mining professional.

Another miner from Kwekwe warned that when boiler attendants add acid during the digestion process, miners move away, leaving room for boiler attendants to steal again.

“During acid treatment, gold maybe scooped out of the pot if you are not carefully watching,” said the Kwekwe miner.

He warned miners to be cautions during the weighing of gold, where he said old water or water that has been added salt to it alters the density measurement of extracted gold in favour of the buyer.

Such gross theft has led various tertiary institutions, through their innovation hubs, to develop mining models that extract at least 90 percent of gold.

Last year, the Faculty of Mining and Mineral Processing at the Midlands State University (MSU) developed a multi-facetted milling model that incorporates a stem mill, a roller crusher and a cyanidination tank.

The 3 in 1 gold milling prototype incorporates a boiler for further processing of activated carbon while the stem mill is expected to increase gold production output to 90 percent. ENDS//

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