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By Malcolm Scoble, Yves Lizotte, Ajit Singh

Fragmentation size assessment faces difficult problems, traditionally involving tedious and time consuming procedures. Early work had been directed towards developing empirical methods of predicting rather than measuring fragmentation. More recent development of computer-based image processing techniques which derive size distributions by analysis of photographic or video images are reviewed. These are now being adapted by various workers to fragmentation analysis in mines. Results are presented from experimental work aimed to establish the accuracy and precision of photographic techniques for muckpile assessment. Reference is made to McGill fragmentation studies at surface and underground mines in Canada, relating to experience gained in photographic and image processing techniques. The various factors that affect such techniques as well as their limitations and strengths are discussed.

Jan 1, 1990

By Larry R. Fletcher

Excessive flyrock, which is blasted rock that travels beyond the secured blast area, is responsible for 25 pct of the blasting injuries that occur in surface mining. Excessive flyrock is also a frequent cause of damage to mine equipment and facilities.

Jan 1, 1986

By Judy Konya Bowles, Calvin J. Konya

Blast vibration and air blast are commonly blamed for damages to residential as well as commercial structures. Mining and construction companies are often required to spend monies in court defending themselves even when vibration and air blast levels have been monitored by seismographs and are extremely low.

Jan 1, 1992

By David E. Siskind

In the period 1989 to 1994, the U.S. Bureau of Mines assisted the Office of Surface Mining, Reclamation and Enforcement (OSM) in studying a high-complaint situation near an active surface coal mine. As part of a review for its project report, the Bureau had to address issues on the adequacy of the safe blasting criteria and analysis procedures in its 1980 report RI 8507, Structure Response and Damage Produced by Ground Vibration From Surface Mine Blasting.

Jan 1, 1996

By T Michael LeBlanc

Drill trajectory deviation is a recurring problem in vertical retreat stoping operations. As a result of this deviation, 60 kilogram (165 millimetre diameter) and 103 kilogram (302 millimetre diameter) explosive charges are routinely detonated beyond ore/waste contact zones. Consequently, there follows a reduction in finished stope wall stability and an increase in ore dilution.

Jan 1, 1996

By John Brennan

Necessity, they say, is the mother of invention. Certainly that sentiment held true during the early stages of explosive engineering. While seaside forts were concerned over static ignition of their black powder caches in the 14th century1, the mining industry in the 1800s were plagued by accidents surrounding the ignition methods for their black powder blasts.

Jan 1, 2011

By Lewis L. Oriard

The purpose of this paper is to provide an overview of close-in blasting effects on various types of structures and building materials, as encountered in this writer's professional practice. Structures range from old, deteriorated historical monuments to new, heavily reinforced buildings. Materials range from clay adobe to concrete and steel. Site locations range from tropical to arctic. Blasting ranges from sculpture blasting inside buildings to "coyote" blasting and large surface blasting operations. Space limitations permit a brief discussion of only 25-30 specific cases, but they have been selected to be typical of conditions found on hundreds of similar cases. The writer was asked to present a discussion of representative cases where relatively high vibration intensities were experienced. Virtually all of these cases were free of damage, but the few damage cases provide valuable insight to the mechanisms involved. Observations of such damage and non-damage cases have served as the basis of this writer's criteria for various structures and materials, as well as the technology to conduct blasting operations within those criteria. A sampling of these experiences is gladly shared with the reader.

Jan 1, 1991

By A T. Spathis, J J. Felice, W Klass

Cast blasting has become one of the most efficient ways to move waste rock in open cut coal mining. It is used at Mount Thorley Mine in conjunction with a dragline to move some of the overburden onto the spoil dump.

Jan 1, 1992

By Joshua Micah Hoffman, Catherine E. Johnson

The recruitment and retention of future talent into the explosives industry is becoming increasingly important. One potential area from which future talent can be recruited is local student chapters. Many of the student chapters are closely connected with engineering programs. While this makes sense and both entities benefit from these arrangements, there is a trend of job placement primarily in the engineering industry. Before the explosives industry can begin to compete with other industries, it should be determined what is drawing the students into these other fields. The work presented in this paper sought to better understand the collegiate student population from which a portion of future explosives professionals will emerge. This was done through the use of an anonymous online survey distributed to the student members of the International Society of Explosives Engineers, as well as, members of SEE student chapters. The survey contained questions about future job and career plans, ideal job placement, and expectations of salary. The purpose of the survey was to determine what these students expect or require from a career in the explosives industry. This information can help steer recruitment activities and job offers. Through understanding what is incentivizing these students who have accepted or plan to accept jobs in other industries the explosives industry can better posture itself to be more competitive in recruiting from the collegiate talent pool.

Jan 1, 2014

By R. Jacob

Mining has been around for a long time, and new deposits are being discovered continually but are becoming more complex for processing and typically sulfide in nature. Most of the large easy deposits with simplified and cheaper to process oxide material have been mined or the deposits are locked up with legal or social issues and may never be mined. It is common to see the mines today being evaluated to mine have little in oxides and have a sulfide component to the deposit. This creates a problem with explosives being selected for the mine because ANFO could cause a reactive ground issue. When evaluating the cost component of mining for future mines, ANFO is the go-to selected bulk explosive because of the cost and effectiveness. More work needs to be done by projects evaluating costs by properly testing the ground and water conditions to match the correct bulk explosive for the ground conditions of the mine. This will prevent a possible safety hazard and the best result for the mine.

Feb 6, 2023

By Frank Sames

Blast vibration and airblast overpressure signals are generally rated and compared only by their maximum amplitude and the principal frequency associated with the peak pulse. The scaled distance concept is often used to predict peak amplitudes and can be applied for blasts in the same area of a mine to evaluate the statistical properties of a set of readings.

Jan 1, 1997

By E. Contestabile, B. von Rosen, P. Lightfoot

As part of an accident investigation ANFO was subjected to various abusive tests. A tractor-trailer carrying 18,000 kg of blasting explosives, caught fire, burned for approximately 30 minutes, and then detonated. A series of tests was designed to observe the behaviour of ANFO when subjected to different thermal stimulus tests and more specifically, the Height-to-Detonation Test. Three diameters of steel pipes were used in the Height-to-Detonation Tests thereby simulating cylindrical columns within a pile of ANFO. The ANFO samples were then subjected to various thermal stimuli to initiate a reaction. Through the use of some instrumentation, the response of large ANFO samples was recorded and its behaviour, including the occurrence of phase changes will be analysed.

Jan 1, 2001

By Gungor Tuncer, Erhan Bakirci, Ali Kahriman, Atilla Ozmen, O. Nuri Ucan, Savas Gorgun

There are several methods for demolition of structures but most of them depend mostly on conventional ways of using machines for breaking and crushing structural elements. However the need for lots of work force, expense and extreme amount of time for demolition, made most of these methods non-popular nowadays. Therefore, trials to accomplish a more economic and less time taking method lasted with the use of blasting. By applying controlled blasting on a suitable structure, the structure can collapse and break down to pieces in very short period of time, with no extra work force and cost. In spite of advantages of explosive demolition, the potential danger of explosives and the damage that the blasting may cause to surrondings, if not controlled properly, made people timid to the method especially in urban areas. Therefore, the pre-assumption by computational analysis has become an essential matter in the process.

Jan 1, 2002

By V Krishna Mohan, J Edmund Hay

This paper discusses the results of the gap sensitivity measurements made on water-gel explosives, sensitized by monomethylamine nitrate (MMAN) and flake aluminium, and one emulsion explosive. This study specifically deals with the effect of the mode of initiation, end or center, on the measured L50 values with air gap and coal dust gap for the above explosives. Similar measurements have also been carried out on a nitroglycerine (NG) - based explosive. The results show that the mode of initiation plays an important role in determining the air-gap sensitivity of these explosives. However, in tests carried out with the coal dust gap, the L50 ( grams of coal dust ) values for these explosives are close in both the types of initiation. The results indicate that the sensitivities of these explosives may be ordered in the following manner: NG-explosive>> Aluminized explosive ~ MMAN-explosive > Emulsion explosive

Jan 1, 1982

By Paul V. Sterk, James Wieser

Mining in underground situations requires constant change due to changing ore bodies and economics. The Homestake Mine in its 122 years of existence has gone through numerous changes due to these factors. Recent sustained low prices in gold and ore bodies that are smaller or within mined out areas have forced the mine to reevaluate how these ore blocks will be mined. This paper will describe the design, drilling, and blasting of a complex ore block using the blind raise uphole bulk mining method.

Jan 1, 1999

By G Alan Foster

Because of the marked human response to blast effects and inherent defects present in many modern structures the real possibility of being named as a defendant in a law suit faces most blasters. Until recently even frivolous law suits involved a great deal of expense since legal costs were inevitably incurred whilst waiting for your day in court, which typically occurred some 2-4 years after the alleged damage took place.

Jan 1, 1989

By Dave Proudfoot, Mike van Wyk

"There has akvays been plenty of discussion around the ‘accuracy of pyrotechnic detonators withmost recognised manufacturers claiming a variability of arourid 1% or less for their ‘superaccurate’ pyrotechnic based detonators. It is only now being understood that this 1% variabilitycan have serious adverse effects on blast performance. For example a 1% accurate 500millisecond shock tube detonator can fire anywhere between 485ms and 515ms. When wecouple these rather inaccurate ‘accurate’ detonators with short delays on surface, such as a 17millisecond connector, the probability of delay crowding and even out of sequence firing is quitehigh."

Jan 1, 1998

By ISEE

Micrometer Crack Response to Vibration and Weather, by Prof. Charles H. Dowding of Northwestern University, adds to Prof. Dowding’s already important contributions to the industry with his “Construction Vibrations” books. This new book reports and interprets important data on crack response that are essential for differentiating the unseen effect of weather on structural cracking from the usually much smaller effect of vibration. In addition, the book contains detailed descriptions of data collection methodology.

Jan 1, 2010

By Michael J. Sapko, Eric S. Weiss, Richard W. Watson

As part of the Bureau of Mines research into the hazards associated with the mining and processing of oil shale, experimental mine tests have been conducted to evaluate preferred combinations of explosives and inerting materials to prevent ignition of oil shale dust and mixtures of oil shale dust and methane.

Jan 1, 1989

By Jacques Monette, P K. O'Connell, Keith Boyle

The mine contracting industry in Canada is no different from any other industry in its quest for productivity improvements. Dynatec Mining Ltd. has focused on drilling and blasting of rounds as an area for improvement. This paper describes the development of blasting long rounds in shaft sinking as well as a description of the lateral excavation system as applied at Aur Resources Inc., Louvicourt Project.

Jan 1, 1994