Integration of iron ore deposit evaluation and mine plan for selecting cost effective beneficiation operations towards improved resource utilisation: Experience at Tata Steel

Abstract

In the recent past a paradigm shift in terms of resource utilization and beneficiation practices is experienced by the Indian mining and mineral sector. Depleting iron ore reserves coupled with increasing demand for low-alumina iron ore fines to improve blast furnace performance in terms of productivity and reduced slag rate necessitate intensive beneficiation of iron ore. The task is even difficult for Indian iron ores which are generally high in iron content and at the same time characterized by aluminous gangue and thereby calls for capital investment of higher order for beneficiation. In another direction, any beneficiation means rejecting some mined ore as waste for obtaining the desired product grade and involves costs. Hence, beneficiation option has to be used judiciously. Towards this, the enabler available is characterization and assessment of geological resource to explore the options of segregation, scheduling, sequencing and blending. Joda East Iron Mines (JEIM), which caters to approximately 45% of iron ore requirement of Tata Steel plant in Jamshedpur, and has its ambitious plan for upgrading existing beneficiation facilities in the form of ‘Total Beneficiation’. The paper describes the judicious beneficiation and effective utilization efforts made, in the light of characterization and assessment of deposit, mine planning over last 10 years as experienced by JEIM plant and also discuss the importance of blending of processed ores in achieving despatchable product grades to meet customer requirement while optimizing overall ore resource utilization. JEIM has modified to earlier only washing plant to present two beneficiation circuits, namely Wet and Dry Processing plants, to take care of off - and high grade ores, respectively. The Dry processing plant is quite simple, comprising crushing and dry screening with no tailings/wastes. Off grade material is concentrated through primary and secondary crushing followed by screening and oversize crushing and re-screening, washing and sizing, scrubbing, classification in classifier and hydrocyclone, with a overall weight recovery of ~87%. The journey in improving product quality while optimizing plant production in JEIM relates to changes in operational philosophy which basically could be related as “identifying correct methods of ore dressing for correct ore” in line with deposit ratio.