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A Blasters Journal - Pattern Expansion

Tales from a Stope – Pattern ExpansionFrom the overblasting note that was written on October 23 in “Tales from a Stope – Overblasting”, it was noted that the starting point for pattern expansion was the ANFO pattern - 1.82 m x 2.12 m (burden and spacing) using 115 mm up-holes. This was the initial baseline point for commencing a pattern expansion program using emulsion explosives pumped into up-holes from the collar. IRECO Canada 2 (later Dyno Nobel) re-pump bulk emulsion RUS would replace ANFO.
At the time (1990’s), there really weren't any calculation tools to determine powder factors/energies accurately because of the oblique nature of long hole drilling in sub-level cave stopes along with the fact that blasting models were almost non-existent. Computer technology was in its infancy so most design was experienced sourced or hit and miss trials. The common theme was that if fragmentation suffered (too big), then pull the pattern in, regardless of what explosive was being used. …
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New Blasting Software Optimizes Fragmentation .... Article by Sudbury Mining Solutions Magazine

Before: This photograph shows obvious overbreak with damage to screen and bolts owing to a pattern that was too tight (blastholes too close together).
North Bay’s iRing Introduces Aegis Break Analyzer New software designed to turn underground mine blasting into primary crushing is triggering early success on two continents. Aegis Break Analyzer, software to optimize mine drilling and blasting, developed byiRing Inc. of North Bay, was used to design the best blasting pattern for an underground stope at Goldcorp’s Eleonore gold mine in northern Quebec. At a mine in Chile, Aegis was used to identify the optimal design for blasting with ANFO explosive. “It’s a tool that allows a mine to really do extensive cost analysis and performance analysis,” said Chris Preston, a professional engineer and iRing’s vice-president of research. Blasting operations designed by Aegis Break Analyzer can diminish reliance on expensive underground crushers as the main means of delivering fragmented ore to a mill …

A Blasters Journal - Overblasting

Tales from the Stope - Overblasting  The year was 1991, and I had just joined IRECO Canada 2 which was initially based in Montreal. Its Canadian distributor was CANEX EXPLOSIVES in Brossard Quebec. I would represent IRECO in Sudbury as a research engineer for both IRECO and INCO LTD. The intent was to compete for a five-year explosives supply contract (100%) amongst other competitors such as NORDEX, ETI (Explosives Technologies International) and last but not least ICI (Imperial Chemical Industries). For a five-year contract, the emphasis was on business partnership which differed from the standard explosive customer-supplier relationship of the past. Each explosives manufacturer had their own wrinkle and kit of tools to attempt to win over commercial explosives users such as INCO. As it turned out, IRECO got a five-year contract supplying 90% of the explosive business including detonators, ANFO, water-gelsand emulsions along with accessories such as primers and cords. Work started im…

AEGIS Break Analyzer - What It Is And What It Does

iRing INC has developed a new technique for analyzing/diagnosing blasting patterns based on a stress reflection principle and a unit charge blasting geometry.  In addition to five analytical blasting calculators, there is one main Blast Design workflow. The intent of providing these tools to underground blasting operations is to allow engineers and planners the ability to see the effect of explosive types, rock/ore parameters and stress generation on ring blasting as well as discovering how varying specific parameters and properties of both explosives and rock/ore types influence blast pattern design. AEGIS Break Analyzer Objective
AEGIS Break Analyzer is designed to benchmark current blasting practices as well as provide insight into new patterns and practices. Based on dynamic explosive properties and dynamic rock properties, Break Analyzer matches the explosive detonation state (shock - brisance) and explosion state (gas expansion - heave) energies in order to maximize ore recoverie…

How to Deal with the Lack of Shock Attenuation Information for a Rock/Ore Type

There is nothing worse that trying to determine solutions for very specific blasting problems when hard data is missing. Most underground mining operations do not monitor seismic wave-forms as part of their best practice processes except when blasting operations are close to population centers. This is usually done to determine magnitudes of seismic vibrations that may disrupt homeowners and businesses. Monitoring blasting operations with seismic equipment can be used to develop the data needed determine shock intensities versus scaled distances away from specific blasts either by charge weight or charge energy. This information is key in developing shock attenuation versus scaled distance curves for predicting vibration levels at distance. Shock-wave Travel in Rock/Ore - Dispersion and Impedance Mismatch Contribution to Attenuation Characteristics The detonation of an explosive charge fully coupled in a borehole results in high borehole pressures with steep rise times. This pressure …