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Harum Energy mines coal from the different mine sites in East Kalimantan, using open-pit along strike strip mining methods. To date, maximum mine depth can be achieved up to approximately 60 meters using 250-tonne class hydraulic excavators and 85-tonne to 100-tonne off-highway dump trucks to mine both waste and coal seams with mining commencing at shallow cover and continuing down dip. Once mining operations at a pit is completed, the land is rehabilitated and restored to its natural state as much as possible. This may involve backfilling the pit and replanting vegetation to promote ecosystem recovery.
Harum Energy's mine operations can be impacted by adverse weather conditions, particularly during the monsoon season from October to December, when heavy rains can slow overburden removal and reduce coal production volumes by up to 15%. Harum Energy's mine planning function anticipates and adjusts production levels to take into account such weather-related delays and Harum Energy also set the minimum stockpile level and stockpile intervals along the route in order to mitigate the impact of weather-related delays.
Trucks transport coal directly from MSJ's and SBB's mines and travel up to 50 km to the coal processing, stock-piling and barge loading facility at Separi, located on the banks of the Mahakam River. Separi stock-piling and barge loading facility which consists of conventional coal handling equipment, including weigh bridge, ROM stockpile, crusher, crushed coal stockpile, reclamation system and barge-loader, an elevated single rear dump station, equipped with a receiving hopper and a primary crusher designed to pass coal at a rate of 1,000 ton per hour (tph). Gravity screening of undersize and secondary crushing at a rated capacity of 1,000 tph then allows for the coal to be placed on a conveyor to a traveling tripper on a sky conveyor to a 240,000-tonne capacity crushed coal stockpile or directly to a barge-loader.
Almost all of the coal sold by Harum Energy is loaded on the customers' vessels in the open sea. At Separi port, coal is loaded onto barges (typical capacity 8,000 ton each) and transported to the open sea transshipment anchorages at Muara Berau (approximately 140 nautical miles or 265 km). The coal is then transferred into the customer's vessels using the vessels' own cranes, in the case of geared vessels, or using separate floating cranes, in the case of gearless vessels. Barging is conducted by a subsidiary, LLJ, which owns and operates a fleet of tugboats and barges.
The production of refined nickel involves several stages, starting from mining of nickel ore to the refining processes, which stages are interconnected with the objective transforming nickel ore into high-purity nickel suitable for a wide range of industrial applications, from stainless steel production to battery manufacturing.
The refining process begins with the extraction of nickel ore from open-pit mines. Once mined, the nickel ore is transported to the stockpile for further drying, crushing and grinding processes. Thereafter, it will be continued with the smelting process using reduction kiln to reduce or remove certain impurities to get intermediate products with suitable specification for further refining process.
Then, such nickel intermediate products will undergo further refining process to produce higher-purity nickel using certain technologies.
The refining technology uses by each of IMI, WMI, SNMI and BSE are varied. IMI and SNMI produces refined nickel, using rotary kiln electric furnace (RKEF) technology, in the form of nickel pig iron, whilst WMI’s RKEF technology is equipped with converter to produce high-grade nickel-matte (see production flow below). Further, BSE is designed to produce nickel-cobalt hydroxide intermediate product (Mixed Hydroxide Precipitate (MHP)) using high-pressure acid leaching (HPAL) technology.
