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By Khushaal Popli, Vanessa Roeland, Brian Hall, Carl Diederichs

Highland Valley Copper (HVC) has embraced an integrated Mine to Mill approach to comminution since the late 1990s. Previous blasting optimization was carried out through adjustments to blast pattern geometry (i.e., reduction of burden and spacing). This approach proved very effective and HVC reduced the burden and spacing of high energy ore blast patterns to what was considered the practical limit that still allowed for efficient drilling and bulk truck loading operations. While mining in the bottom of the Valley pit near the end of the previous pushback, HVC encountered high static groundwater conditions which enabled the transmission of elevated inter-blasthole pressures that had the potential to exceed safe operating limits for initiation products. This risk was mitigated through an expansion of burden and spacing for the high energy ore patterns, reducing the application of blasting energy and increasing the average particle size in Mill feed.

Feb 6, 2023

By James Rowland, Richard Mainiero

When most people think of explosives transport they think of a hazardous operation. We all know that we aren’t allowed to transport explosives through tunnels and are discouraged from traveling through heavily populated areas. Popular opinion suggests that explosives transport is a very risky operation. The authors decided to look into this a little more thoroughly and found just the opposite to be true.

Jan 1, 2008

By María Rocha, Benjamín Cebrián, Roberto Laredo

"Ring blasting designs have to achieve different goals in order to become efficient whether is done in up hole or downhole fashion. Ore recovery/dilution control, fragmentation and drift integrity all have to be taken into account when selecting parameters such as burden, spacing, linear explosive density and stemming. Blast energy simulation allows identifying contours of rock breakage and fragmentation, thuschoosing a combination of spacing at the end of holes and appropriate burden. Also, simulations are keyto concentrate energy levels on the mid part of the ring while making sure there is not too high of energy concentration around the drift, which integrity is needed for a safe ore mucking."

Jan 1, 2017

By Johan Gjødvad, Catherine Aimone-Martin, Charles Dowding, Mathias Jern

A residential structure adjacent to a quarry in Ohio was instrumented to record structure motions, resulting wall strains and existing crack displacements in response to close-in blasting within 82 m (270 ft). The project is a cooperative effort among international experts representing the European Federation of Explosives Engineers (EFEE) and ISEE supported by more than 21 persons from eight different countries to compliment prior work performed at the Aitik Mine in northern Sweden. The focus of this study is to compare blast-induced vibration measurements relative to regulatory compliance limits as a percentage of allowable velocities among eight different countries for a one-story residential wood-frame structure with a brick-and-mortar exterior and full basement. Participating counties included Austria, France, Germany, Norway, Sweden, Switzerland, the United Kingdom (UK) and the United States (US). Geophones were placed on the foundation and in the ground in accordance with each country’s regulations to record peak velocities as a function of frequency or distance to blasting. This study extends the work performed at the Aitik Mine to include interior corner geophones to calculate global wall strains and micro-m (micro-in) displacement gauges mounted over an existing drywall crack to measure blast-induced dynamic crack responses and climatological influences on daily opening and closing of a crack. Structure responses were documented for 68 blasts conducted north of the structure from February through September 2023 of which 17 blasts were selected for detailed analyses. The highest in-ground PPVs recorded were 43 mm/s and 59 mm/s at the NE and SW corners, respectively. Measurements from these blasts plotted within each country’s limits provided a comparison of stringency among the counties. The percentage of compliance limits among counties ranged from an average of 114% for the US, UK, and Austria limits to the highest of 585% for Switzerland. Despite these high percentages of compliance for all countries, the global tensile strains induced by these blasts were at most only 12 μ-strains and occurred with the highest velocity blast that exceeded each county’s limit. This high percentage of compliance and low strain level demonstrates the restrictive nature of the regulations studied. Peak dynamic crack opening and closing during blasting averaged 20 -m (0.0008 in) while the 12-hour weather-induced crack displacement during the time period over which blasting occurred averaged 200 -m (0.008 in) and the largest 12-hr change in crack width was 356 -m. This low level of crack response validates the observation that the studied regulations have highly conservative limits for cracking potential of standard building materials.

Jan 21, 2025

By Ian Bell, Saman Nouranian, Shahram Tafazoli, Bahram Sameti, Mahdi Ramezani

"Image-based rock fragmentation sensing in mining and quarry applications includes an important rock boundary delineation step, which is commonly referred to as rock segmentation. This paper presents a novel approach to solve this problem, using artificial intelligence. In the proposed technique, priorknowledge of previously analyzed images is encoded into mathematical/statistical models. A set of human labeled images are used as training inputs. These images are used to train neural networksthrough an optimization process. The networks can then be used in real time for rock delineation. "

Jan 1, 2017

By P. Ross, O. Rielo, P. Katsabanis

Selection of delay times to optimize fragmentation has been a controversial topic among researchers and blasting practitioners. The paper reviews all available experimental information, ranging from small and medium scale tests in geologic materials to small scale tests at the laboratory and synthetic materials, simulating rock. Tests have been re-analyzed and discussed in terms of the information they present and the limitation of the testing environment in representing actual conditions. New results obtained from blasting experiments in specimens made of a grout have provided a clear picture of the effect of delay on fragmentation. The grout used has a strength of 60 MPa (8700 psi), density of 2.5 g/cm3 and P-wave velocity of 4000 m/s (13100 ft/s). Each block was placed in a yoke to eliminate unwanted reflections and the desired delay was obtained using the appropriate length of detonating cord between holes or sub-millisecond electronic detonators. Delays ranged from 0.1 ms/m (0.03 ms/ft) of burden to 16 ms/m (4.9 ms/ft) of burden. Fragmentation was obtained using screen analysis of the collected fragments. Delay time has been shown to be a significant parameter affecting fragmentation and back break. Generally larger fragments and less back break was observed at short values, while fragmentation somewhat deteriorated at significant delay times, compared to what was observed at intermediate delay times. The work is now extended to include the effect of energy partition on fragmentation as well as the effect of initiation point and coupling ratio.

Jan 1, 2014

By Adrian Moore, Bryan Goodwin, David Fales, David Lam

This paper describes the development of blasting protocols used to successfully create a 450m long blast fractured permeable trench in a basalt aquifer up to 20m thick, at a petrochemical facility in Australia, to enable the remediation of contaminated groundwater.

Jan 1, 2011

By J. Silva, M. Kotraba, F. Pontanilla

Blasting is the application of highly complex science that, in some cases, could be viewed as an art. Many variables are involved in a blast, including geology, pattern design, timing and firing sequence, and explosives selection. Assuming that better results can be achieved by only increasing the powder factor is inaccurate. The Drill-to-Mill (D2M) concept has been in the mining industry for over two decades. The D2M approach is commonly viewed in an oversimplified manner, assuming that by simply increasing drilling and the amount of explosives used (both of which add operational costs), the downstream value will be created. An optimized D2M initiative should combine the smart application of explosives at the beginning of the mining process, matching the dynamic properties of the rock to the explosive selected to improve the efficiency of the energy created by the explosive to the rock mass being blasted, and to bring benefits to the mining operation across the entire mining and processing value-chain. This paper reviews the principles behind matching the shock impedance of the rock and the explosive and compares the traditional use of explosives versus the smart application for two hypothetical blasts.

Jan 1, 2024

By M. Ganster

Austria’s biggest supplier of oil and gas, transports gas through the West Austria Gasline for domestic consumption. In addition, the OMV also works as gas carrier and ensures the transit into neighbouring countries.

Jan 1, 2010

By John L. Didlinger

We all hate the paper work in keeping accurate blasting records. Nevertheless, have you ever thought what those records could show you? Think about it. Those records could show you vibrations, noise, and safety problems. They could show you the ratio of powder used and tons produced, the cost per foot, even help negotiations for pricing.

Jan 1, 1997

By H. S. Venkatesh, G. Gopinath, R. Balachander, G. C. Naveen

Punatsangchu Hydroelectric Project Authority is constructing 1020 MW underground hydroelectric project in Bhutan. The project envisages construction of concrete dam, Desilting Chamber, Head Race Tunnel, Power House Complex and Tail Race Tunnel. Tunneling is one of the major activity in any underground projects as they are driven for multiple activities. By and large the tunnels are a major part of connecting networks from surface to caverns/underground working sites. Many tunnels in hydropower project are part of water conducting systems and one such important tunnel is the Tail Race Tunnel in this project and had to be excavated in thinly foliated rockmass conditions by D&B method.

Feb 1, 2020

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

By Mark S. Stagg, Siskind David E

The mining industry occasionally blasts near pressurized transmission pipelines and has requested guidance on safe vibration levels and setback distances. The Bureau of Mines and the Indiana Department of Natural Resources cooperated with AMAX Coal Company on a study of coal mine overburden blasting. Five buried and pressurized 250-ft pipeline sections were specifically installed on the Minnehaha Mine highwall near Sullivan, IN for testing to failure. Four welded steel pipes ranging from 6- to 20-in diameter and one 8-in PVC water supply pipe were monitored for vibration, strain, and internal pressure for a period of 6 months while production blasting advanced up to the pipeline field. In contrast to previous studies of small-scale blasting representing construction activities, these tests involved overburden blasts of up to 2100 lb per delay in 12-1/4-in diameter holes.

Jan 1, 1993

By Cam Thomas

"Reflectorless laser survey equipment has made it much easier to take accurate measurements toinaccessible locations in quarries, open pit mines and rock slopes. Prior to the introduction of thereflectorless laser as a working tool, it was not possible to directly measure to inaccessible locations on rock faces. If a person could not occupy the point, only indirect measurements could be made. For blasting work, measuring the burden in front of the first row of holes could only be done approximately, using such techniques as holding a plumb line in over the crest, triangulating in on a few points or “eyeballing” the burden. This led to direct and significant problems with blasting, including flyrock and airblast (caused by insufficient front row burden), excessive vibrations, problems with oversize and tight digging (all of which may be caused by excessive front row burdens)."

Jan 1, 1999

By Brent Blanchard

As most veterans of our industry are aware, explosive demolition by its very nature is often a challenging proposition. Even under the best of circumstances, proper planning and care must be taken during a variety of processes to ensure a safe, successful result. However, every now and then a project suddenly arises where safety, timing and cost factors combine to form a critical scenario requiring rapid execution in an environment far more challenging than the norm. On these occasions, the stresses, complications - and most notably the dangers - related to the industry increase exponentially, and conspire to test the mettle of even the most seasoned experts.

Jan 1, 2003

By BruneJurgen F., Richard C. Gilmore, Matthew Schreiner, Ray Johnson

Explosive pockets of methane-air mixtures accumulate in underground coal mines and, when ignited, produce an air-blast wave that can disturb combustible coal dust on the floor, roof, and ribs. To prevent explosions, the coal dust must be continuously diluted through application of inert rock dust, usually powdered limestone. Application of powdered dust process creates a respiratory nuisance downwind, where miners cannot work until the dust settles. Rock dust suppliers have developed wet and foam applied products to reduce the nuisance and limit the interruption to mining during dust application. To test the effectiveness of these alternative dust products, researchers at the Colorado School of Mines (Mines) have constructed a full-scale explosion test drift located at the Mines Edgar Experimental Mine (Edgar) to study the dispersibility of different rock dust applications. This paper examines the use of Pentaerythritol tetranitrate (PETN) detonating cord to produce controlled air-blasts that simulate methane-air explosions. The air blasts are generated with curtains of detonating cord that produce shockwaves with wind speeds between 30 to 70 m/s (100 to 225 fps) depending on the length of 5.3 g/m (25 grain/ft) detonating cord used. These velocities represent the minimum air speeds required to trigger propagating coal dust explosions. Researchers have conducted 40 test blasts with various lengths of detonating cord. Results show the two primary waves and two reflected waves each decaying into airblast waves with overpressures of 14 to 27 kPa (2 to 4 psi). Pressures were recorded with commercial piezoelectric transducers and custom-built, bi-directional probes to record the total and dynamic pressures of the wind generated in the explosion. Researchers were able to generate consistent and repeatable wind speeds and air-blast durations sufficiently similar to a methane-air explosion to study the dispersibility of various rock dust products and application methods

Jan 1, 2019

By Richard J. Mainiero, Eric S. Weiss

This project investigates the behavior of blast waves from the detonation of high explosives in an underground mine. A series of explosive tests was conducted in the underground and surface facilities at the Bureau of Mines' Lake Lynn Laboratory to evaluate the potentially dangerous effects of blast waves produced by open shooting, blown out holes, or accidental detonations of explosives. Shots of C4 and TNT were fired at the dead end of a 6 ft high by 20ft wide entry, at the intersection of two entries, and on the surface. C4 and TNT were chosen for this research because they exhibit very consistent performance. Behavior of the blast wave was evaluated through recording of the pressure as a function of distance from the explosive detonation.

Jan 1, 1995

By Bruce R. Leland, Steven H. Smith, John D. Paulson

The USDA - Wildlife Services has been removing beaver dams with explosives for over 30 years. This paper will discuss the history of the explosives program, summarize how we've evolved, and highlight our work removing beaver dams in unique locations.

Feb 1, 2020

By Paul Ross, Harry Burchett, Lou Case, Calvin J. Konya

"The Cumberland River in Harlan, Kentucky has flooded the town for numerous years. TheU.S. Army Corps of Engineers funded a project to divert the river. The project consisted oftunneling through a mountain to divert the river. The approaches to the tunnels requiredcontrolled blasting to create noses to help channel the water and debris into the tunnels.The geologic structure was such that conventional presplitting techniques were notproducing the desired results and were causing severe backbreak. Replacement of the rocknoses with concrete would cost about a million dollars; and therefore it was important tosave them if at all possible. Blasting techniques were developed which allowed the projectto be successfully completed. This paper will discuss the case history of the controlledblasting procedures."

Jan 1, 1993

By Mauritz Kotze, Jason Furtney, Ewan Sellers, Sandy Etchells, Tom Szendrei

The development of a simple model for gas flow and burden movement has driven the need to improve our understanding of burden breakage mechanisms for single hole blasts and the interaction between multiple holes in solid and jointed rock masses. Conventional analytical understandings of the burden breakout using the elastic-tensile fracture model were studied and found to provide a breakout angle that is independent of burden in contradiction to experimental data. By considering rock fracture in terms of Mohr-Coulomb plasticity using analytical expressions from the field of cavity expansion analysis an improved relationship between breakout angle and burden is derived until the point of critical breakout at which the angle of breakout suddenly changes from between 90 degree and 100 degrees to zero. This suggests that the critical burden occurs at about 0.6 times the radial fracture zone calculated from the analytical solutions.

Jan 1, 2013