Advanced vibration management to improve productivity and optimize cost for excavation of iron ore: A case study

摘要

A major concern in deep hole blasting in open cast mining operation is the excessive generation of ground vibration and their effect on nearby industrial infrastructures and residential dwellings of local community. A poor blast output results in lower productivity of excavators which has a paramount adverse effect on overall cost structure of mining operation. Drilling and blasting cost comprises a significant part of the overall operations and maintenance cost in an open cast excavation process. The paper describes the result of systematic study carried out to manage ground vibration and blast output parameters at Joda East Iron Mine, which has an annual excavation of 12.5 MT (FY 16). The study involved detonation of multiple blast holes to determine the effective charge weight per delay and generate site specific empirical equations and constants. A further detailed study was then carried out using stastical - simulation technique to specify the blast designs and delay pattern for reducing the blasted mean particle size of rock strata which has a compressive and tensile strength of 145.3 MPa and 13.6 MPa respectively. The average density of rock is 3500 kg/m3. A correlation was then established between drill feed pressure and rock hardness to optimize the explosive charge per delay. The peak particle velocity data were recorded at point of interest. This data was subsequently analyzed for developing the limits of vibration. A correlation model was then established between predicted and actual vibration at point of interest. The result showed approximately 90% accuracy between these parameters. Electronic delay detonators were introduced for controlling the blast design parameters with variation in the explosive charging methods. A comparative study was then simulated for measuring the cost effectiveness in overall mine to mill operation which resulted in a significant amount of cost saving over the entire value chain. Paper also represented the overall range of cost and blast output parameters in different rock strata of iron ore and has several recommendations for enhancing blast output, which have suitable benefits in mining industry.