Flowability Characteristics of Iron Ore and Their Influence on Material Handling System Design Parameters

The total production of iron ore in India was 246 million tonnes in 2019–20 and 188.6 million tonnes (estimated) in 2020–21, according to the annual report 2020–21 of the Ministry of Mines. Odisha state is the leading producer of iron ore accounting for nearly 59.64% of total production followed by Chhattisgarh (14.11%), Karnataka (12.76%), Jharkhand (10.93%) and remaining (2.56%) production reported from Andhra Pradesh, Madhya Pradesh, Maharashtra and Rajasthan. The production of millions of tonnes of iron ore involves intensive material handling operations including storage and conveying the Run-of-Mine (ROM) and finished product. During the handling of the iron ore in interplant processing, the ore is stored in stockpiles or silos, and transported by means of a series of conveyors that is accomplished through transfer chutes. The flawless movement of iron ore during the entire process plays a key role in realizing the highest levels of productivity and plant capacity utilization. However, iron ore flowability problems like plugging/choking of transfer chutes, and arching/bridging/ratholing in silo/stockpiles are often encountered especially while handling wet and sticky ores during monsoon and post-monsoon seasons. This necessitates having a scientific understanding of the flowability characteristics of various grades of iron ore simulating the field conditions. The material handling systems are required to be designed and tailor-made based on the flowability characteristics established by standard test methods simulating field conditions. The flow properties are dependent on particle size distribution, particle shape, chemical composition, moisture content, and temperature. The present study involves the evaluation of flow properties of different grades of iron ore samples collected from the Odisha-Jharkhand region and the calculation of design parameters for material storage and handling systems, like silo/stockpiles and transfer chutes. The influence of flowability characteristics on various material handling system design parameters was analyzed.