A Comparative Analysis of Rock Fragmentation using Blast Prediction Results

Abstract

This work presents prediction and optimisation of controllable parameters of drilling and blasting currently used at the Fobinso Pit of Perseus Mining Ghana Limited (PMGL). The mine faces challenges with blast particle sizes produced after primary blasting. The presence of boulders requires secondary fragmentation to further reduce the broken materials to the acceptable sizes, thereby increasing the cost of production. The mechanical properties of the rocks were determined using Protodyakonov Rock Strength Index. The drill and blast parameters were estimated using the Konya and Walter (1990), Principle of Proportionality, and Instituto Geologo Minero de España (IGME) model developed in 1987. The Modified Kuz-Ram model was used to predict and analyse the results of blasting based on the parameters such as spacing, burden, drillhole diameter, charge density, charge per hole, charge length, and powder factor. A comparative analysis of the predicted size distributions of the various models using diameters of 65 mm and 110 mm revealed no significant differences between the size fractions. The Principle of Proportionality produced the best technical and economic indices for blasting. Keywords: Fragmentation, Drilling Parameters, Primary Blasting, Models, Secondary Blasting

Influence of natural discontinuities and mechanical properties on the fragmentation of marble by blasting in Central Africa

“…Bidzar's model is reliable with 100% of the blocks passing through the 250 cm mesh crusher (Fig. 7 to 9) because, according to Agyei et al (2019), all prediction models produce similar distribution patterns with more than 90% of the blocks passing through the 300 cm mesh crusher.…”

“…This compares with models obtained in other regions of the world, notably in Northern Europe, Central America, South-East Asia and West Africa. Thus, Biessikirski et al (2019) predicts 96.38% and 99.98% respectively of passers in mesh crusher of 100cm and 200cm using drill hole 105 mm, Mariz et al (2019) predict that 80% and 99.90% respectively of passers in mesh crusher of 85.6cm and 200 cm using drill hole 88.9 mm, Shaib et al (2020) predict 100% of passers in mesh crusher of 100 cm using drill hole 76 mm and, Agyei et al (2019) and Ninepence et al (2016) predict respectively 96.6% passers in mesh crusher of 300 cm using drill hole 115 mm and 80% passing within the optimum size range of 100 cm using drill hole 165 mm. Bidzar's model is reliable with 100% of the blocks passing through the 250 cm mesh crusher (Fig.…”

“…The size of the fragments obtained should also not exceed the opening of the crushing plant for efficient operation (Jug et al, 2017;Shaib et al, 2020). The presence of large blocks requires secondary fragmentation to further reduce the material pulled to acceptable sizes, thereby increasing production costs (Rustan, 1990;De Lile, 2012;Mohammad et al, 2018;Yahyaoui et al, 2018;Agyei et al, 2019). In general, when blasting, there is not always a match between the size of the blocks shot and the size of the crusher mesh.…”

Explosive utilization efficiency enhancement: An application of machine learning for powder factor prediction using critical rock characteristics

“…To get the fragmentation you need, you have to make sure that things you can control, like the blast geometry and explosive properties, work with things you can't, like geological conditions and legal limits [ 27 ]. Blaster design factors such as burden, spacing, stemming, bench stiffness ratio, and powder factor all have a significant impact on the fragmentation that occurs after a blast [ 28 ]. By manipulating these factors, it is possible to achieve the most favorable fragmentation, resulting in mean fragment sizes that can vary between 50 % and 200 % [ 28 , 29 ].…”

Examining the Effect of Powder Factor Variability on Granite Productivity

“…The effectiveness of hard rock blasting is measured with two basics indices namely, oversize generation and blast hole productivity. Cost per tonne of rock blasted is another index that measures the effectiveness of blasting and is dependent on rockiness and blast design parameter such as hole diameter, burden, spaces among others [9,10]. Such parameters differ from one mine to the other and some of the blast design parameters could be regulated to deliver the desired blasting effectiveness.…”