The borax method of gold extraction for small-scale miners

Peter W.U. Appel, Leoncio Na-Oy

Research output: Contribution to journalArticleResearchpeer-review


Background. More than ten million small-scale miners (SSM) worldwide use mercury to extract gold, releasing large amounts of the toxic element into the environment. Alternatives to mercury have been suggested over the years to little avail. A group of miners in the Philippines has demonstrated that borax, when used as a flux for smelting gold out of heavy mineral concentrates, is an effective and safer substitute for mercury.

Objectives. To present a basic comparison of the mercury amalgamation and borax methods of gold extraction for SSM.

Methods. Borax was added to milled ore to reduce the melting point of gold to a level accessible to SSM. The amount of gold captured, and the amount of mercury released into the environment, was compared to two common amalgamation methods: whole ore and heavy metal.

Discussion. The borax method appears to capture more gold, as well as eliminate the use of mercury. It is also less expensive. It is important to stop the use of mercury amongst SSM. However, health and environmental arguments alone are not enough to convince miners to switch. The argument of improving gold-capture rates while reducing costs is more compelling, and may help propagate the technique among small-scale miners.

Conclusions. Scientific research should continue in order to further establish the uses and limitations of the borax method.
Original languageEnglish
Pages (from-to)5-10
Number of pages6
JournalJournal of Health and Pollution
Issue number3
Publication statusPublished - Jun 2012

Programme Area

  • Programme Area 4: Mineral Resources


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