Mercury use and emissions in small-scale gold mining in southeastern Mindanao, Philippines and the need for intervention.

• There are several small-scale gold mining operations scattered throughout the Philippine archipelago occupying about 50,000 miners and mineral processors. The sites with the larger number of miners involved are located in Southeastern Mindanao, Philippines, particularly in Compostela Valley Province. Our objective is to relate observations made in relation to mercury use in small-scale gold mining in the Philippines. Although the useof cyanide has been introduced, mercury amalgamation for gold recovery is still, in a number of operation sites, the dominating method. Amalgamation tailings (aside from unprocessed ore) are generally further processed in a cyanidation plant because most gold is left after amalgamation. Amalgamation and cyanidation tailings are usually dumped into improvised, generally leaking, dams or directly in the surroundings. Mercury is thus released into the environment by direct disposal or seepage into rivers and unconfined blow torching of mercury amalgam. There is no complete record or inventory of mercury importation for use in small-scale gold mining operations. Amounts of mercury releasedare not documented and reliability of estimates is poor. Recovery and recycling of mercury has not been commonly practiced because the efforts are not commensurate to any large monetary savings, although there is presently an increasing interest in economizing mercury use as an effect of increased mercury prices. Records of high levels of mercury in sediments and waters within and downstream mining areas indicate significant releases of mercury. It has been estimated that 50 tons of mercury might have been released annually into the rivers in the Diwalwal gold-rush area, the largest smallscale mining operation in Mindanao, at the height of the gold rush from 1986-1988. Releases declined then to 26 tons annually, which was further reduced to 17 tons annually in the past two years. These emissions threaten the ecosystem as well as the workers and their families, also in communities downstream. Therefore education campaigns, global initiatives to restrict mercury availability and a continuous strict enforcement of existing regulations on mercury use must be prioritized to reduce theareas and the numbers of individuals affected by mercury pollution.

Publikations- och innehållstyp

vet (ämneskategori)

kon (ämneskategori)