SURIGAO CITY (MindaNews/13 September) – The Mines and Geosciences Bureau (MGB)-Caraga has urged small-scale miners in the region to use cyanide instead of mercury in the process of recovering gold from ores.
Noli N. Arreza, officer in charge of MGB-Caraga, on Thursday told participants to the Small-Small Miners Congress held in this city that his office is heeding the request of the Regional Agricultural and Fishery Council that was made through a resolution.
The resolution asked the MGB and local government units to help promote the use of cyanide, not mercury which Arreza said is still being used by some miners. It was passed during the council meeting on June 24 this year in Butuan City.
“The council is considering the alarming alleged mercury pollution from the mining tailings of the small scale mining operations,” the resolution read.
It added that through the Environmental Management Bureau, the council learned that using cyanide is a better option than using mercury in processing gold.
Arreza said mercury is a toxic chemical that poses danger to the environment.
“Although cyanide is also hazardous, it can easily react with sunlight once exposed and also can be treated by chemicals using sodium chloride,” he said.
In an interview, Arreza could not say how many small-scale miners are operating in Caraga Region saying they are still doing an inventory.
He said that during the late 1930s miners poured several barrels of mercury into the river near Barangays Mat-i and Mabini in Surigao City to extract gold.
Mat-i is the city’s watershed where small-scale miners have continued to operate. Earlier reports said the miners had cut down several trees in the area for their tunnels and bunkhouses.
Arreza said large-scale mining companies in Surigao del Norte also used mercury before.
Cecilia L. Consuegra, chief chemist at MGB-Caraga warned the congress participants about the ill-effects of mercury.
“Mercury is a silvery-white liquid. At ambient temperature and pressure, it readily vaporizes and may stay in the atmosphere for up to a year,” she said.
She said mercury may be fatal if inhaled and harmful if absorbed through the skin. Around 80 percent of the inhaled mercury vapor is absorbed in the blood through the lungs.
“It is harmful to the nervous, digestive, respiratory and immune systems,” she said, adding exposure to the chemical “can cause tremors, paralysis, impaired vision and hearing, insomnia, attention deficit, and developmental delays during childhood.”
Ansel Espanto, a small-scale miner operating in Bad-as, Placer town in Surigao del Norte said that contrary to accusations he is not using mercury for his gold and silver processing plant.
Espanto said he is practicing responsible mining by building waste treatment facilities.
According to the International Cyanide Management Institute (ICMI), cyanide is extremely toxic to humans.
“Chronic (long-term) inhalation exposure of humans to cyanide results primarily in effects on the central nervous system (CNS). Other effects in humans include cardiovascular and respiratory effects, an enlarged thyroid gland, and irritation to the eyes and skin. No data are available on the carcinogenic effects of cyanide in humans via inhalation,” information posted in ICMI’s website said.
ICMI noted that cyanide came to be widely used in the latter part of the 19th century as a reagent for the leaching of gold because it costs less compared to other reagents like chloride and bromide. (Roel N. Catoto/MindaNews)