GOLD MINING IN MUBNDE.
“The most common occupational diseases that workers are likely to develop as a result of long-term exposure in the gold mining environment are silicosis, silico-tuberculosis, pulmonary tuberculosis (TB), obstructive airways disease, occupational asthma, oral and/or nasal cavity erosions, diseases owing to ionising radiation, noise-induced hearing loss, whole body and hand-arm vibration syndrome, as well as repetitive strain injuries,” says Mepha.
He adds that the preventative measures for mineworkers who are exposed to high levels of occupational health hazards are inadequate. “Substitution, isolation, correct engineering, protection equipment, education and awareness all need to be improved to help keep mineworkers safe from harm.”
The surrounding communities, which are referred to as nonoccupationally exposed populations, reside in close proximity to the gold mining activities and can be affected at various levels.
“The adverse health effects may result from environmental exposures to air, water, soil, and noise pollution,” says Mepha, who adds that a mineworker exposing his or her family to whatever he or she has contracted, after being exposed to hazardous work environment, can be equally harmful.
Factors which determine health hazards and their potential severity include the type of pollutants concerned, the dose or concentration of pollutants and the age or devel- opmental stage of the person exposed, as well as the duration and route, such as inhalation, ingestion or dermal contact, of exposure.
Prolonged exposure to gold mining activi- ties can cause many life-long problems for workers.
“Airborne dust, with a high concentration of more than 5% of alpha quartz silica, can cause occupational lung diseases, such as cardio-pulmonary TB, silicosis, silico-tuberculosis, obstructive airways disease and occupational asthma. Short-term exposure can cause a worker to suffer irritation of the upper respiratory tract (nose and throat) and lower respiratory tract (alveoli),” states Mepha.
He adds that welding and flame-cutting fumes can cause chronic obstructive pulmonary disease and other diseases, such as occupational asthma, coughing and wheezing, while the inhalation of mercury vapour can have harmful effects on the nervous, digestive and immune systems, as well as on the lungs and kidneys, and may be fatal.
“Neurological and behavioural disorders may materialise after inhalation, ingestion or the dermal exposure of different mercury compounds. Symptoms include tremors, insomnia, memory loss, neuromuscular effects, headaches and cognitive and motor dysfunction,” Mepha notes.
He says that mild subclinical signs of central nervous system toxicity can be observed in workers who have been exposed to an elemental mercury level in the air of 20 μg/m3 or more for several years. Effects on the kidneys have been reported, ranging from increased protein in the urine to kidney failure.
“Repetitive strain injuries from heavy lifting and working with the body in awkward positions can lead to injuries of the arms, legs and back. The use of jackhammers or other vibrating machinery can cause damage to nerves and negatively affect blood circulation, which could lead to a loss of feeling in the limbs or dangerous infections, such as gangrene, and even death,” he notes.
In most South African mines, uranium is produced as a by-product of gold mining, which can expose workers to radiation levels higher than the yearly limit of 20 mSv a year.
Excessive constant noise from machines can cause hearing problems, including deafness, while working underground for long hours with insufficient light can harm vision.
Working in hot conditions without drinking enough water can cause heat stress, signs of which include dizziness, weakness, a rapid heartbeat, extreme thirst and fainting. “Non-environmental exposures, such as mining disasters, can affect the community indirectly and directly,” Mepha says, adding that air pollution caused by power plants and smelting factories situated near mines causes serious illness.
“The conditions in the mines are being compromised as a result of the increasing number of experienced occupational hygiene/ventilation engineers who are leaving the gold mining sector,” he says.
Mepha adds that these engineers are likely to leave because of retirement and better remuneration and working conditions in other sectors.
Meanwhile, some mining companies are using technology rather than relying on the skills of individuals to improve the conditions at gold mines.
The Mining Industry Occupational Safety and Health task force and learning hub, aims to address the major risks involved in working in the mining industry, such as noise and silicosis.