High-quality thermal coal produced from coal overburden

Coal production in the world’s largest archipelago

It sounds like something from the world of fantasy, where Jules Verne meets J. R. R. Tolkien. A country comprising over 17,000 volcanic islands in the ocean. An archipelago that is home to 262 million people. A remarkably diverse nation drawing together hundreds of ethnic groups who speak more than a dozen languages. A tropical climate featuring monsoon winds. Fiery red volcanoes that are the domain of the Komodo dragon. Beautiful white beaches with water of purest turquoise. And at the heart of the Coral Triangle, a jungle inhabited by elephants, orangutans and tigers.  

But far from being fantasy, this land is quite real: it is none other than Indonesia, the fourth-most populous country in the world. And PT Suprabari Mapanindo Mineral, a company based there, commissioned allmineral to craft a system solution for processing high-quality thermal coal. This project was a great success – by processing the coal/ash spoil generated by selective mining, the new coal-washing plant also delivers economic and ecological benefits. 

The challenge: delivering cutting-edge allmineral processing technology to Kalimantan

In order to meet growing demand on the global market, one of the most cutting-edge coal processing plants in the world was planned for the newly tapped mining region of Kalimantan on the island of Borneo as part of a pioneering project. This represented the perfect challenge for the Hazemag subsidiary allmineral, which was commissioned in November 2019 to plan, equip and deliver a modern coal processing plant to its final destination 11,000 kilometres away. The customer required a tailored system solution that could produce and process 500 tons per hour at this 350,000-hectare coal mining facility. 

The Astra Group signed up allmineral to handle the implementation of this major investment, having been impressed by the company’s wide-ranging specialist knowledge, years of experience, and targeted expertise relating to tailored and creative solutions. Creativity was central to this project, as the saleable coal product needed to be extracted from the spoil rather than being drawn directly from the coal seam. Spoil is generated during selective mining, with its very high ash content meaning that it is usually discarded.

In order to meet these requirements, it was necessary to deploy cutting-edge processing technology capable of using a washing process to sort sub-bituminous and bituminous coal featuring different sulphur content levels. The research department at the Global Testing & Research Center duly drafted an individual system solution to help the coal-washing plant guarantee maximum quality and durability in line with customer requirements. This involved a delicate balancing act between the high tonnages to be processed and the resource-conscious handling that was required.

The answer for full-scale wet processing – a system solution based on the alljig®

Within a period of 12 months, allmineral drafted, produced, delivered and installed a coal-washing plant centred on an alljig® jig. Equipped with a high-performance roller breaker and a chain conveyor from Hazemag, the processing plant is designed to separate the coal from unwanted components and sort it into the various qualities in an efficient, sustainable and resource-conscious manner. The three-chamber alljig® jig meticulously sorts up to 500 tons of coal per hour, handles grain sizes ranging from 80 mm to less than 1 mm, and ensures efficient, fully automated sorting, concentration and cleaning of coal.

As reliable as it is cost-effective, the alljig® F(UB) 5000 x 3400 first loosens the material prior to processing and uses water power to raise it up. After the jigging procedure sorts the grains by density, the alljig® separates the light feed (coal product) from the layered material bed. The ash is classed as the heavy feed and is subsequently dewatered on a dewatering sieve using cutting-edge sensors whose signals are detected and processed electronically. This enables precision discharging of the heavy feed.

The results speak for themselves, with the coal-washing plant featuring a capacity of 500 tons per hour and able to generate high-quality thermal coal ready for shipping worldwide.