Kawah Ijen is a 2799 meter high active vulcano in West Java, which has a one-kilometer-wide turquoise-colored acid crater lake. The lake is the site of a labor-intensive sulfur mining operation.
An active vent at the edge of the lake is a source of sulphur. Escaping volcanic gasses are channeled through a network of ceramic pipes, resulting in condensation of molten sulfur. The sulphur, which is coloured deep orange when molten, pours slowly from the ends of these pipes and pools on the ground, turning bright yellow as it cools down and hardens. The cooled sulphur is broken into large pieces and carried out in baskets by the miners.
Average loads range between 70 to 100 kilograms. About 250 miners carry the sulphur from the crater lake approximately 200 meters up to the crater rim before they start the several kilometres descent down the mountain.
The miners get 500 rupiah (about 5 US dollar cent) per kilo sulphur they carry down and most men make the journey twice a day. So they earn an equivalent to approximately 5.00 US Dollars a day. Most of the sulphur is sold to a nearby sugarcane refinery and is also to the pharmaceutical industry who use the sulphur in skin-care product.
The miners use insufficient protection, often only a wet cloth they put in their mouth while working in the poisonous sulphur-oxide gasses around the crater, and are susceptible to numerous respiratory complaints. According to the World Health Organisation their average life expectancy is only about 30 years.
The job often is passed on from father to son.