FLSmidth aims to commission the dry tailings stacking systems and paste at the lead-zinc mine in Rajpura Dariba, Rajasthan state, by February 2022. Financial details of the order, which was booked in the fourth quarter of 2020, have not been disclosed.
The main pieces of equipment in the order are two Automatic Filter Presses (AFP-IV), two E-Disc filters and one 26m-Dia High-Density Thickener.
The tailings dam used for both Rajpura Dariba and Sindesar Khurd - India's largest underground mine - is reaching capacity for conventional wet tailings deposition, said the company.
The project involves the creation of a small dry-stack tailings area with minimised environmental footprint, and a method to backfill the mine using an adjusted dry filter cake mix. This new order follows a previous tailings-related order for Hindustan Zinc Limited at their Zawar mine site in 2018.
FLSmidth said it will use a combination of the E-Disc filter and the AFP-IV Automatic Pressure Filter to recover around 85% of process water. The cake from the E-disc filter will contain below 16% moisture and be used for mine back filling, while the cake from the automatic filter press, with below 12% moisture, can be stacked on the surface.
"This project resolves the customer's challenge through optimum utilisation of available space and ensures the paste backfill requirements are met with the lowest possible operating and capital costs," said Manfred Schaffer, mining president, FLSmidth.
Hindustan Zinc's Sindesar Khurd mine is India's largest underground mine, with production of 5.1 million t in FY 2020 and an average reserve grade of 5.9%.