Tuesday 24 December 2019

Collapse at illegal gold mine kills six in Jambi Province, Sumatra.

Six people have been confirmed dead following a collapse at an unlicensed gold mine in Jambi Province, Sumatra, on Sunday 22 December 2019. The incident happened at about  1.00 pm local time in the village of Pulau Baru following heavy rains in the area. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. One of the deceased has been identified as a local man, the other five are reported to have come from Central Java. Unlicensed mining operations in Indonesia are notoriously unsafe, and also cause a variety of environmental problems associated with indiscriminate digging, with some mining haven taken place inside national parks.

Rescue workers at the scene of a mine collapse in Jambi Province, Sumatra, on 22 December 2019. Basarnas.

The site on which the mine was operated had apparently been leased from a local landowner for the purpose if mining by two businessmen, who's identities have not been released for legal reasons while there is an ongoing investigation. The mineworkers were apparently using mercury to extract gold from ore at the site, a process in which ore is mixed with mercury to remove the gold, then the resulting amalgam of the two metals burned to remove the mercury, effectively evaporating it off, resulting in large amounts of fumes. There are means of extracting gold from ore without mercury, but this is the simplest method on a low technology base. Mercury is a highly potent neurotoxin, and can cause a variety of other health and developmental problems in children; it is considered to be particularly harmful to infants and fetuses. The fumes are persistent in the atmosphere and can travel long distances, which places those not directly involved in the amalgamation process at risk, since the process is often carried out in residential areas, and close to streams from which drinking water is extracted and fish are caught and eaten. On this occassion waste from the process was being dumped into a local river, which had already caused local villages to stop using it as a sourse of drinking water. Local authiorities are extremely concerned about the potential impact of this on settlements further downstream, including the city of Jambi, which has a population of about 600 000.

Sumatra has a wet tropical climate, with a rainy season that lasts from October to April, when rainfall typically reaches 200-300 mm per month and a dry season from May to September, when rainfall is usually below 200 mm per month (though the area is never truly dry. This is driven by the Southeast Asian Monsoon Seasons, with the Northeast Monsoon driven by winds from  the South China Sea fuelling the wetter rainy season and the Southwest Monsoon driven by winds from the southern Indian Ocean the drier dry season. Such a double Monsoon Season is common close to the equator, where the Sun is highest overhead around the equinoxes and lowest on the horizons around the solstices, making the solstices the coolest part of the year and the equinoxes the hottest.

The winds that drive the Northeast and Southwest Monsoons in Southeast Asia. Mynewshub.

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