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Eloranta J.,Eloranta and Associates Inc.
Journal of Explosives Engineering | Year: 2014

The economic relationship between blasting and grinding through a model is described. Mesabi Range taconite blasting parameters are used to predict break even cost reductions in grinding that would be required to offset various blasting expenditures. Reconciliation of mine indicated versus plant actual ore grades is a common practice. Optimization of mine or mill fragmentation energy requires the same approach. Capital costs are very high for conventional flow sheets in today's market. A base case design for Mesabi Range is used to establish a starting point for cost comparisons. Modeling indicates that the ranges of cost increases are within the range of 24 hours variations in mill throughput. Clearly, there are many other factors that impact mill throughput. Source

Eloranta J.,Eloranta and Associates Inc.
Journal of Explosives Engineering | Year: 2013

This article compares the cost of glass microballoons (GMBs) to grinding costs. In large diameter blasting, microsphere sensitization is sometimes overlooked since gassing or porous prill additions can allow the emulsions to detonate and in many cases appear to give reasonable results.The additional cost of adding GMBs may be viewed as expensive until a more detailed performance analysis is undertaken. Different means of sensitization can result in substantial changes in explosive behavior. Energy expended late in the combustion process may not be conducive to the development of microfractures necessary for efficient subsequent grinding. Reactions occurring at the C-J front may play a much larger role in the creation of microfractures than those occurring after the front had passed. Although it is a separate topic, granular aluminum has also been added to the model. Aluminized ANFO has been an effective product in taconite. However, several authors have cast doubt on the addition of granular aluminum to emulsions. A simplistic model suggests that the cost of adding 1% GMBs would be offset if grinding costs dropped by 1.2%. If 3% granular aluminum is also added, then powder costs would be offset if grinding costs dropped by 4.1%. Source

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