The Zimbabwe Miners Federation (ZMF) has warned gold buyers and the mining industry over a rise in sophisticated gold tampering, with fraudsters now using foreign nationals, mainly Chinese, alongside local Zimbabweans to alloy gold with hard‑to‑detect metals.

ZMF President Henrietta Rushwaya said the scam deliberately targets small‑scale miners because their gold is often bought using the specific gravity method at regional buying centres, where spot payments are made on delivery.

In contrast, large‑scale miners’ gold is subjected to fire assay at Fidelity Gold Refinery’s Head Office in Harare, with payment only after accurate analysis, a protocol that protects large deliveries from adulteration.

According to Rushwaya, the troublesome elements being introduced include ruthenium, which has a very high melting point and complicates refining and fire assaying; mercury, a highly toxic substance that poses environmental and health risks; zinc, which can be alloyed with tungsten to mask tungsten’s density and evade specific gravity tests; and iron, which interferes with sampling and fire assay procedures.

She said these elements are deliberately used to manipulate both XRF readings and physical density tests. Fraudsters are able to achieve specific gravity readings of 90 to 95, readings that appear plausible but hide the true composition. Said Rushwaya:

“The Chinese are the chief culprits using Zimbabweans to perpetrate this thievery. We are warning gold buyers: do not buy gold without using an XRF machine, but also understand that XRF alone is no longer enough.

“I recommend that gold buyers invest in a high‑calibrated XRF machine to improve detection. If a Chinese national comes to sell gold to you, be on high alert.”

She noted that handheld XRF machines only analyse the surface of a bar or pellet, and fraudsters exploit this by layering or creating homogeneous alloys that fool the XRF into reporting high gold content.

Even the water displacement method is being defeated because tungsten has a density nearly identical to gold, and when alloyed with zinc, the overall density can be manipulated to mimic pure gold.

Rushwaya said fraudsters are deliberately targeting small‑scale miners because their consignments are often not subjected to fire assay at the point of sale.

The artisanal and small‑scale mining sector now accounts for more than 70% of total gold deliveries to Fidelity, making it both vital to the national economy and increasingly vulnerable. Said Rushwaya:

“We are going to name and shame those involved, including black Zimbabweans who are used to advertise and front these deals.

“We are hunting them down. Those responsible should be arrested because they are stealing from the country’s treasure. This is economic sabotage.”

The federation said it will push for stricter regulations and enforcement to close the loophole threatening the integrity of Zimbabwe’s gold sector.

https://news.pindula.co.zw/2026/03/27/zmf-to-name-and-shame-locals-and-chinese-in-gold-adulteration-scam/