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By Michael Olmsted

Inspection of boreholes prior to blasting can result in cost reductions as well as increases in efficiency and safety. Until recently, borehole inspection was performed in two manners. For simple inspections, a flashlight was used to view the upper part of the hole. More thorough inspections were performed with long tool strings developed for oil field applications. Borehole inspection tools developed specifically for mining and blasting applications have now been developed. Video Cameras developed for borehole inspection have been in service for several years. Now measurement tools are available, developed specifically for mining.

Jan 1, 2000

By Jerry Wallace

The goal: At an industrial site, sever a well pipe containing an interior obstruction in a timely, cost effective manner by using a shape-charge to cut through the casing more than 50 meters below ground surface from the outside, doing so while inside a larger pipe, without damaging the larger pipe. The problem: Pumps and retrieval tools stuck nearly 50 meters below ground surface inside a 305 mm diameter by 9.5 mm wall thickness water well casing. The well, depth of 185 meters, had to be inspected for contaminates then properly decommissioned before industrial expansion could take place overhead. The limitations: A 508 mm diameter pipe had been driven around the 305 mm pipe to a depth of 63 meters. The usable internal diameter of the larger pipe was about 480 mm while the smaller pipe had buckled at one point forming a 350 mm wide spot. The charge thickness was limited to less than one-half the difference. Additionally, water that filled the annular space between the two pipes had to be displaced for the charge to work properly. The solution: Enlist the support of the shape-charge manufacturer to design, build and test a charge to work under the conditions present, then make it work in the field.

Jan 1, 2000

By Luis Valentim, Terry Cousins

The goal of a mine is to produce ore at the lowest possible cost with due regard to safety of pemonnel and equipment. The mining process consists of a number of discrete operations such as planning, drilling, blasting,excavation, transportation and crushing. These processes are interrelated and cannot be considered as separate activities when optimising output and minimising cost. In order to optimise the global costs it may therefore be necessary to increase cost in one area such as blasting design and management beyond the norm.

Jan 1, 1998

By AJ Rorke, JD Botes

Presplit blasting in strip mines is aimed at creating a safer wall to work under during the coaling operations. Good quality presplits are also necessary for effective throw blasting and drainage of the blast block. A less obvious but important function is full coal recovery. Optimum Colliery has been experiencing rock freezing against the presplit highwalls. The rock formed in patches along the highwall and trapped coal beneath it. The material that was &ozen comprised the rock between the back row of holes and the presplit and was often up to 3 m thick (the stand off distance between the back line and the presplit). The cozen rock formed predominantly along the bottom halfor bottom two thirds of the highwall. Along the top portion of the highwall, the presplit crack was usually well formed with visible barrels. This problem, or similar variations of it, is common on many South African strip-mine operations. Investigative work was carried out at Optimum Colliery to correct the problem. This paper presents the information and measurements that were made and discusses the solutions that have been applied to solve the problem. It was found that there were two independent causes for the tiozen material, with each contributing more or less to the frozen rock along the highwall. It was found that the presplit was not forming properly in places, especially closer to the bottom of the highwalls. The reasons and the solutions are presented. The second cause was found to be associated with reduced detonation velocity in the back line holes coupled with low confinement from long delay periods. Emulsion explosive that is sensitised with air bubbles was found to be prone to this phenomenon near the back of high-energy blasts. A change in the explosive formulation in the back-line holes, together with reduced delays in the back line, has resulted in significant improvements. The details are presented in this paper.

Jan 1, 2000

By Stig O. Olofsson

The problem of overbreak in underground construction and mining is normally approached by a variety of smooth blasting methods. Numerous small diameter, low velocity explosives have been developed specifically for blasting the contour line. Increased mechanization in rock excavation has led to the development of several methods of mechanical explosive loading. A new mechanically loaded smooth blasting explosive was developed in Sweden . However, several limitations were realised, which after several trials resulted in a hybrid smooth blasting method, The Suaer Cautious Contour Blasting Method which will be discussed in this paper.

Jan 1, 1994

By Teele Tuuna, Voglers Eesti OÜ

Blasting operations are a strong and important part in any kind of building and mining industry, a shot-firer profession is one of the oldest professions in the civilized world. It still serves an important and ongoing purpose in the modern economy all over the world. Europe, nowadays, values strongly the mobility of workers, the movement of know-how and labor force between different countries inside Europe. There are no borders for most of the everyday professions.

Jan 1, 2018

By Tom Short

"Construction blasting covers a very extensive variety of explosive applications. I will discussseveral of these with you and then show slides from my collection, starting in 1956, which will betterillustrate the types of blasting under discussion."

Jan 1, 1991

By John Watson, Jay Rodgers

The world of blasting and explosive use continues to evolve into one which relies heavily on measurement, quantification, process control, and information feedback as a means of contributing to operational improvements. More than ever good blast performance, once thought to be a result of someone’s “artistic ability”, is giving way to “hard science” and measurement techniques. Variability in product performance and process control is becoming less tolerable with increasing environmental issues, regulatory pressure and public awareness.

Jan 1, 1998

By A Rorke, B Cubitt, R Beeslaar

The recent drop in the value of the South African Rand has resulted in an increased export value for South African coal and has lead to new coal reserves becoming available for mining. Very often these reserves are in close proximity to existing structures and utilities thus calling for stringent blast control measures to keep the risk of vibration, air blast and fly rock damage to a minimum.

Jan 1, 1997

By Brian Gar Wingfield

"The introduction of the QuarryMan laser profile system in 1987, along with the development of the corresponding 3-D software, gave a qualified operator pertinent information about dimensions of quarry highwalls, pattern and hole loading design, stockpile profiles, etc . . . Attributes helpful for this endeavor included surveying, computer, and blasting knowledge. Since not all operators had theseskills, a simpler model, the QuarryAce, was designed to look a t highwall dimensions in 2-D view . Al though less sophisticated than the QuarryMan instrument and its software, it is simpler to instruct in its use and has the ability to determine burdens at different depth levels . An in-house user f r i e n d l y computer program was designed to utilize QuarryAce depth vs. burden data . This program was created to enable laser and computer novices to generate information useful to the everyday blaster."

Jan 1, 1992

By Calvin Konya, Anthony Konya

State and Federal construction specifications require the Blasting Contractor to prepare a Master Blasting Plan which is reviewed by the Owner’s Representative. The Master Blasting Plan requires the Contractor to submit the design of a typical blast. Most blasting specifications also require the Blasting Contractor to submit Daily Blasting Plans. The Master Blasting Plan and the Daily Blasting Plan require that the Blasting Contractor also submit the types and quantities of explosives and initiators used. The specifications also request that the Blasting Contractor submit the pounds of explosive used per delay for both production and presplit blasts. The Blasting Contractor may also be required to predict the anticipated ground vibration and air overpressure levels for the proposed blasts. There are equations that can be used to predict the ground vibration. There are also equations that can be used to predict the air overpressure levels. The data for these equations were primarily derived from quarry and surface coal mine and some construction blasts. Data from major construction projects were analyzed in this study to determine new air overpressure propagation equations for construction blasting. These new prediction equations compare calculated results analyzed from field data with other existing air overpressure prediction equations. Production blasting air overpressure values are also compared to air overpressure from presplitting

Jan 1, 2015

By Dennis R. Jr Bell

Before beginning any site development or mineral extraction activity, it has been well documented that it is first prudent to gain an understanding of the prevailing geologic conditions.Whether it’s identifying the depth to type of bedrock, or determining the quality and quantity of the in place mineral deposit, these factors should always be considered in a project’s fatal flaw analysis. In situations where there is limited subsurface information, geologic models have been proven to be one of the most valuable and cost-effective tools used by the developer and/or his consultant.

Jan 1, 1997

By William C. Geitz

"Lightning has always posed a serious threat to blasting operations, especially wkhin the mining and construction industries and operations involving the manufacture, transport, storage and handling of explosives. In recent years, technological advancements in communications systems and microprocessors have significantiy improved the accuracy and efflliency of lightning detection and warning instrumentation. These advancements have increased the availabilii of highly reliable,accurate and affordable systems for use within the explosives arena."

Jan 1, 1991

By Don Novotny, Dana Spencer

In this workshop our intent is quite simple; that is that we will introduce a relatively new technology that may have applications in blasting applications. This technology is the laser initiation of explosives. This workshop course is not intended to suggest ways in which specific blasting problems can be resolved. That is the purview of experts within each of your fields.

Jan 1, 1994

By Mike Higgins

"Data management is emerging as a major concern for miners. Engineers today are faced with anextensive array of data from varying sources, and are required to consolidate and analyse thisinformation to produce an effective and efficient mine plan. The viability of a mining operation canbe dependent on the outcomes of this process. With so much at stake, it is no surprise that mostengineers prefer a standard approach to blasting which is designed to minimise risk rather thanoptimise performance."

Jan 1, 1998

By Craig Wilbour, John Stimberis, Rob Gibson, Lee Redden

An avalanche is a snow slide. A simple explanation is that the snow on a slope will slide (avalanche) when the snow strength can no longer support its own weight. Snow avalanches happen when the load from snowfall or ram on a snow slope increases faster than the stre n g t h of the bonds between snow crystals. Avalanches can also happen when the strength of a buried layer decre a s e s . Active avalanche control is the intentional triggering of slides. Washington State Department of Tr a n s p o r t a t i o n (WSDOT), does avalanche control to minimize the chance of natural avalanches into traffic. Avalanche control work is done all over the world by: highway departments, ski resorts, railroads, mining operations, utility companies, and other activities threatened by avalanches. The majority of active avalanche control is done with skis, by explosives, or exploding projectiles. Blasting techniques and practices have evolved to fit the specific needs of avalanche contro l . Passive avalanche control is the use of engineered s t r u c t u res such as snow sheds, bridges, or snow supporting devices, to permanently protect a specific location from avalanches. The problem is that these struct u res are extremely expensive. There are a variety of passive avalanche control measures as well as the active m e a s u res used to protect the highway over Snoqualmie Pass. As traffic volume and use expectations incre a s e , m o re extensive passive measures will be needed to keep avalanches from affecting the highway.

Jan 1, 2004

By Tom Palangio, Ralph M. Olmstead

Video inspection of boreholes with cameras developed specifically for the mining industry is now possible. These designs are reliable, cost effective, and have the flexibility to be used in other applications.

Jan 1, 1998

By Carl Lubbe, Ron Frye

Numerous articles have been written regarding the effects of blast control plugs in an attempt to quantify stemming ejection rates, air overpressures, fragmentation’and other parameters measured using these devices. In an effort to further attempt to understand the function of these devices, field and laboratory research conducted with various stemming devices was performed to enhance existing data sets and analyze otherphenomena that occur when these products are used.

Jan 1, 1998

By Gordon Revey

Over ten million pounds of explosives are used daily to blast rock in mines, quarries and construction projects throughout the United States. Despite the immense volume of explosives used, serious incidents involving the legal use of explosive materials are rare. Unfortunately, when incidents arise they are well publicized, whereas the great majority of blasting projects-even the most challenging ones—quietly occur without incident or public recognition. Although unfair, media coverage focuses on incidents and/or accidents, and as a result skews the public’s perceptions of our industry. These negative perceptions about blasting profoundly effect our work. Most apparent are the community groups who organize to fight blasting work. However, other impacts are more insidious and have long-term effects on our industry. For instance, planning engineers or government agencies often prohibit blasting to avoid the public’s adverse reaction or because of general fear of blasting impacts. Ironically, as regulations and specifications continue to curtail our industry, the net effect is an increase in the cost of rock excavation. As taxpayers, we suffer needlessly by paying more for government funded construction projects. As blasting professionals we are additionally penalized through loss of work.

Jan 1, 2001

By Thierry Bernard

For many years now electronic initiation has brought the time parameter to the centre of blast designs forever. Although this parameter existed before the era of electronic detonators, Blasting engineers or blasters could not directly handle it; technology imposed it. Only discrete values were available. Today, the fact that we can choose any detonation time for an explosive charge questions the viability of most of the rules applied for blast design. Thus, the very famous charge per delay method, that enables a level of vibration to be forecast at a given distance (“Chapot’s law”), is no longer necessarily valid when using electronic initiation. Therefore, it must be approached in a totally different manner. The KUZ-RAM formula, that allows fragmentation to be forecast, is also subject to the same distortion. The aim of this article is to show how the calculation laws used for blast design are influenced by the time parameter (sequence) and how we can efficiently make the most of this, in particular for vibrations. Copyright ©

Jan 1, 2005