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By Ray Slavin, Remi Proulx

The Meikle Mine is a mature underground gold mine utilizing primary and secondary longhole open stoping method with delayed backfill. Combined production with the newly developed Rodeo Mine is 4700 tons per day (4265 tonnes per day) of ore. The vast majority of Meikle Mine production comes from secondary and remnant stope blocks. Remnant stopes are ore blocks that were left behind in the initial mining sequence due to various reasons. Mining of these remnant blocks has created many challenging blasting situations. The application of electronic initiation to blast remnant stopes has proven extremely beneficial. Electronic initiation has provided the blasting engineer with a high degree of flexibility with respect to timing to successfully extract these difficult stopes. Post blast assessment of the remnant stopes using the mine’s cavity monitoring system (CMS) demonstrates that the mine is maximizing ore recovery and minimizing waste dilution. The largest remnant stope blast to date required 54 holes and produced 6700 tons (6075 tonnes) of ore. Another area where the application of electronic detonators has proved successful is in the extraction of slots in which ground conditions are extremely poor. Taking the slot blasts in one shot with double-decked holes as opposed to two single-decked shots has eliminated the need to clean and or re-drill holes. The ability to open the slots in one blast has helped reduce the total mining cost. This concept has recently been expanded to blast complete stopes in one shot. This reduces the stope cycle time considerably and allows the mine to bring ore forward. Current plans for 2004 are to excavate 50% of mine wide stope production using electronic initiation technology.

Jan 1, 2004

By A. Ravi Kumar

A trench is a structure to accommodate fluid carrying pipelines for water, gas, petroleum products etc. Trench serves the purpose to haul the fluids in bulk over long distances safely and economically. Use of pipeline for moving oil and gas was essentially a post World War II development, but now it has acquired its own importance.

Jan 1, 2008

By Dale Preece, Stephen Chung

Mining and quarrying industries recognize blasting as the most effective method for breaking and removing large volumes of rock. However, the economics of blasting are often offset by the costly trial-and-error approach. Researchers in the field of blasting therefore design models to help eliminate the number of trials before finding the best feasible solution. Because of the complexity of blasting, a capable model would allow the designer to look at more than one variable at a time so that the most critical factor can be tackled.

Jan 1, 2002

By Norman S. Smith, Richard L. Ash

Relationships between the three design factors of borehole burden, spacing, and length that control rock breakage were examined by means of reduced-scale bench blasts in dolomite. A set of three indices were developed for analyzing the differences between fragment-sizing distributions obtained from various design combinations. It was found that the factors were interdependent and the indices were directly related to the common stiffness relationship for solid structures. The burden-spacing-length combinations that produced the best and poorest overall breakage, maximum and minimum overbreak, and least and most toe were determined.

Jan 1, 1977

By Donald H. Matthews

Drilling and blasting is an every day, sometimes routine activity, that is always fraught with catastrophic capabilities. Under the best conditions it is hazardous, time consuming and expensive. Under the worst conditions it may be impossible to perform by any but the most skilled specialists. Under all conditions drilling and/or blasting jobs are relatively difficult and require specialized equipment, materials and skills that are uncommon. This paper reviews some-of the jobs and problems handled by one drilling and blasting specialist to show the many varied types of problems requiring the services of specialists.

Jan 1, 1976

By Calvin J. Konya

When blasts are designed, we normally assume the best case situation. We assume that all burdens and spacings will be properly drilled, holes will be properly loaded, initiators will fire at the nominal time and the explosives will release their full energy. This type of precision can be obtained at a machine shop where precision equipment is available to do machining, however, in the field, no matter how well a blast is designed on paper, it most likely will not be done in the exact manner in the field.

Jan 1, 1990

By J W. Edl, F C. Wu

In instrumented model rock blasting experiments in granite blocks, best fragmentation results were obtained when delays between holes were 1 to 2 milliseconds per ft. of burden and when a rectangular shothole pattern was used with spacings larger than the burden. Effective fragmentation in multiple hole blasts seemed to depend primarily on the full development of the crack network around each hole before the charge in the next hole was detonated. The test results showed that simultaneous or almost simultaneous initiation of shotholes in bench blasting resulted in poor fragmentation.

Jan 1, 1975

By Stewart A. Silling, D. Lynn Gordon, C. Mick Lownds, Dale S. Preece, Ali Bhuiyan, Patrick R. Bowden

Blast heave modeling and prediction utilizing the new discrete element model, GEM, that treats rock as elements with alternating arcs and line. Explosive loading of GEM elements is accomplished by utilizing the Noble-Abel equation of state to track the gas pressure from detonation through expansion to atmospheric pressure.

Feb 1, 2020

By Robert McClure, Carlton Lehman

Rendering safe explosives in an urban environment presents a unique challenge due to the safety concerns and disruption to the general public. Potential damage to the surrounding homes, businesses, utilities and transportation infrastructure are some of the major concerns when planning the render-safe operation. Engineering controls to mitigate blast effects, such as damaging air over pressure levels, material ejection and ground borne vibration, need to be implemented as part of the operation. Monitoring of seismic and air overpressure during these operations are needed to protect against potential claims when controlled or unplanned detonations occur.

Feb 1, 2020

By Robert McClure, Carlton Lehman

Rendering safe explosives in an urban environment presents a unique challenge due to the safety concerns and disruption to the general public. Potential damage to the surrounding homes, businesses, utilities and transportation infrastructure are some of the major concerns when planning the render-safe operation. Engineering controls to mitigate blast effects, such as damaging air over pressure levels, material ejection and ground borne vibration, need to be implemented as part of the operation. Monitoring of seismic and air overpressure during these operations are needed to protect against potential claims when controlled or unplanned detonations occur. Two recent render-safe operations conducted in and around urban environments dealt with deteriorated, sensitive dynamite and damaged blasting caps. Utilizing innovative neutralization chemicals and processes to render-safe the deteriorated dynamite, while protecting the general public, proved to be the safest, most environmentally responsible and cost-effective way to approach the problem. In both cases, the explosives, old dynamite and detonators were found in abandoned, unlocked magazines. The dynamite was in a significantly deteriorated state, which was evident due to the nitroglycerine found leaking in,around and under the dynamite cartridges. Iron wire permissible electric blasting caps were also found in a corroded condition with exposed explosives and un-shunted lead wires. With occupied buildings within 180 feet (54.86 meters) of the magazines, any procedure (e.g. transporting, countercharging, burning) that could potentially cause a detonation was not an option. In the event of an unplanned detonation during neutralization operations, several blast mitigation methods were employed to safeguard the site. This operation and a similar one with over 1,000 pounds of crushed and buried leaky dynamite were unique since all the explosives were rendered-safe and neutralized on site. The use of advanced neutralization products and filtering processes allowed for a safer, more environmentally responsible way to resolve the problem. The magazines and all residual solids and fluids were tested and confirmed by independent labs to have no explosives residues. The effluents were treated on site, tested and met safe levels, so they were disposed of at a local municipal wastewater facility.

By Scott Scovira

All flyrock incidents have the potential to result in injuries or fatalities that can result in loss of company reputation, license to operate with clients, and bear the exposure to high cost liability. From 2007 to 2009, one NA Quarry and Construction Business experienced a series of flyrock incidents. In the Spring of 2009, this business declared that the frequency and severity of Flyrock Incidents had reached an unacceptable level. A Flyrock Elimination Program was launched.

Jan 1, 2012

By Jhon J. Silva Castro

Blast vibration records used in mining contain unwanted information in the form of noise due to long-period drifts, background noise, and noise due to the conversion of the analogue signal to a digital signal. When recorded signals from blasting are used to find other physical variables, such as going from particle velocity to acceleration or displacement, the additional information in the vibration signal can result in inaccuracies in the estimation of the peak values and more dramatically, the results in displacement or acceleration can be nonzero near the end of the record. There are different proposed methods to clean or filter the unwanted information from the signal. All of the methods are based on finding the best fit of the record average value (baseline) and then subtracting from the record under analysis to produce the desirable adjustment. Different criteria and functions are used to define the best fit. The function to use will depend on the shape of the record average values. The main characteristic of the baseline function is that it represents a low frequency wave. Such a low frequency wave can be a periodic function or a polynomial expression of nth order. According to the order of the polynomial expression, the baseline correction can be linear, parabolic or high order. In this document the detailed procedure and the results for the baseline correction of a blast vibration record using a periodic function and a polynomial expression of different order is presented. The results show that the drift problem when displacement is calculate using velocity records increases with the increase of the distance from the blast.

Jan 1, 2015

By James Camp

"During the 1950's a cement plant was rebuilt along a Missouri River bluff. The escarpmentwas composed of inter_bedded shale and limestone, typical to western Missouri. All of theraw materials needed to produce cement had been mined via room and pillar at the plantsite since the late 1800's. Portions of the mine began to fail in the late 60's., and by the mid70's M.S.H.A. declared all the areas where the lower Winterset limestone had beenremoved from the back to be ""unsafe"". M.S.H.A. explained that no work could beperformed in or above these unsafe areas unless the work itself was to render the area safe."

Jan 1, 1993

By Agung Wibowo

The incident of Ammonium Nitrate explosion in Beirut on August 4, 2020, became a wake-up call to Ammonium Nitrate stakeholders for mining and construction regarding the deadly risks associated with explosives management. This is a very expensive a lesson learned for all parties involved in the storage of explosives.

Feb 1, 2020

By Ruilin Yang

This paper presents a fragmentation model for large production blasts. The model uses peak particle velocity (PPV) induced from the blast as a controlling parameter to predict the fragmentation size distribution. The PPV can be related to shock pressure or strain under a given rock condition. The fragmentation size is calculated at three-dimensional grid points within the blast volume. The grid size defines the calculation resolution of the model. The fragment size distribution is assumed to be in the same form as the crack distribution within a cube (of the size equals to the grid size) surrounding a grid point. The crack distribution in rock from impact is based on the finding from previous researchers (Seaman et al., 1976). The fines and oversized blocks are calculated explicitly. The summation of the size distribution at all calculation grid points over a specified volume of the blast yields an overall size distribution for the volume.

Jan 1, 2015

By Robert Hopler

Torpedoing Wells. – On the completion of the drilling, or when the production is found to decrease, it is usual to “torpedo” the well to increase the flow. This process was patented in 1862 by Colonel Roberts, who believed, with many others, that the oil was contained in crevices in the rock, which might not have been tapped by the bore-hole. He therefore proposed the use of nitroglycerine, gunpowder, or other explosive, to break up the rock at the bottom of the well, so that these rich “pockets” might be brought into communication with the well.

Jan 1, 2007

By John Horgan, Ethan Marcoux

Explosives have been used to demolish many unsafe structures around the world. However, it is unlikely any demolition job has ever involved destroying buildings already buried 40 feet (12 meters) into the world’s largest ice sheet. That is what happened to the original research station at the geographic South Pole, built back in the 1950s, following a series of discrete explosions between 2011 and 2013.

Jan 1, 2015

By Edward P. O'Hern

The importance of the so-called explosives and the increasing extent of their use are evident from the fact that the production in the United States for the year 1910, as shown by the United States Census reports, amounted to the enormous total of approximately 480,000,000 pounds, this being more than double the production of 1905 and more than three and one-half times that of 1900

Jan 1, 2015

By Rolf Schillinger

Transport of Small Quantities of Explosives Material on Public Roads The transport of dangerous goods on public roads is extensively regulated by EU and national law. The transport of explosive material is not only done by forwarders but also by small companies and private persons with the goal of their own use. The following article tries to explain what is allowed and what is not.

Jan 1, 2010

By Michael Milstein

Northwest Research Station said as more and more older dams are removed to benefit fish, it’s become clearer that rivers rework themselves quickly.“Where the dam is relatively small, it’s a quick response,” he said. “The river quickly forgets.”

Jan 1, 2010