Dewatering coal tailings at Khaa Khudag Coal Mine, Mongolia - Case Study
Dewatering coal tailings at KHAA KHUDAG COAL MINE, Mongolia
The Ukhaa Khudag coal mine lies in the heart of one of the harshest climate zones on earth: the southern Gobi desert. In the winter, its pipelines and coal tailings dam would freeze. In the summer, much of its water would evaporate. Faced with these extreme conditions, the mine needed the most robust equipment available to separate water from its tailings for reuse in the coal handling process.
Conquer the elements, conserve resources
To succeed, the customer demanded:
- Tailings dewatering technology with proven reliability in the toughest conditions
- Efficient removal of tailings water for reuse in the coal washing plant
- A trustworthy partner with the capabilities to test and install equipment and train and consult staff in some of the most remote environments and severe weather conditions imaginable
The reference plant in this case was located several thousand miles away in Kuzbas, Russia. It was here that the customer saw a series of ANDRITZ belt presses, still running strong after nearly a decade in operation, with an annual capacity of some 7 million tons. Convinced by the machine’s performance, the customer’s staff were ready to begin planning for a rapid installation of their own.
A continuously operating and efficient series of large belt presses
Eight ANDRITZ CPF 3000 SMX belt presses, including peripheral equipment from flocculant preparation to belt conveyors, were commissioned to solve the mine’s challenges with coal tailings. This choice was motivated in part by the machines’ superior performance in water recovery along with their continuous thickening and filtration capabilities, which enable 40% lower CAPEX and 10% lower OPEX costs, compared with conventional technologies.
The logistic obstacles to delivery and installation were monumental: paved roads were scarce, safety hazards nearly constant, and additional supplies sometimes weeks, if not months, away. To fulfill the order according to the customer’s fast-tracked schedule, extensive planning and contingency scenarios were put in place. Despite these extreme demands, ANDRITZ SEPARATION was able to execute all deliveries on schedule – from mechanical, electrical, and automation installation to system testing, adjustments, and on-site training. Today, Ukhaa Khudag’s tailings dewatering plant is in continuous operation, fully protected from the elements by a compact, weather-proof enclosure.
Better products with far lower water consumption
Thanks to its increased process water recovery, the new plant now achieves water savings of up to 3.12 million cubic meters per year. In a remote desert, this is a critical resource for the mine’s coal washing process. The plant has also seen a 15% reduction in downtime, amounting to at least 1,000 additional hours of operation per year. The resulting product, some 260 tons per hour of dry cake with 28% residual moisture, is now sold more profitably to a nearby power plant, where local fuel supplies are relatively scarce.
Ultimately, it all came down to choosing the most economical solution with the best technical performance – an achievement confirmed when the project was awarded the prize for Best Technology of 2013 in the Mining Journal Awards. But only a close customer relationship, backed by our experienced on-site technicians, could make it all possible under such demanding logistical constraints.