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By Michael A. Barbaglia, Mark William Withey

The lift shot is an essential blast design in the execution of mine creation and expansion plans. Whether it be opening a new quarry, creating a new level in an existing operation, or for control of water, lift shots are utilized to create the desired results. Lift shots by their nature differ from conventional production blasts because they have no free faces for relief of the blast. Due to this fully confined state, the primary direction of the rock movement is vertical, and the potential for excessive vibration and fly rock generation is great.

Jan 1, 1994

By P D. Katsabanis

Image analysis has been proposed to be an accurate and convenient means of measurement of blast fragmentation. The paper compares the results of image analysis to screening using laboratory scale rock piles. The muckpiles ranged from uniform distribution samples to well graded samples following the Rosin-Rammler distribution.Deviations between screened and imaged distributions were observed in most cases due to the loss of fines. Addition of fines in the system improved the result derived by image analysis considerably. It is suggested that techniques for the prediction of fines be evaluated for modifying the size distributions produced by image analysis.

Jan 1, 1999

By Mauro Fornaro, Marilena Cardu, Renato Mancini, Daniele Castano

Tunneling by explosive blasting in civil works isn't merely intended to break somehow a way through the rock, rather to drive a permanent, constant cross section, lined way. The current mechanical excavation v/explosive blasting debate is mainly centered on the concept of the tunnel wall quality; and consequently explosive blasting strategy is founded on contour blasting.

Jan 1, 1992

By Jack Eloranta

This paper describes a method of evaluating shot performance through the use of available mine- data. The mine had already been monitoring the following parameters for other purposes: drill penetration rates, shovel loading rates, crusher throughput, crusher power and crusher hangups. By assigning pit coordinates to these factors, maps showing the location of difficult and favorable blasting are as are identified. Products and techniques are compared by the same method.

Jan 1, 1993

By Clive-Workman Davies, K K. Kabongo, Mensah Frimpong

Given the capital intensity of the dragline operation coupled with rising cost of explosives, the onus is on mine operators to make maximum use of explosives in blasting to assist dragline diggability. At a surface coal mine in South Africa large boulders necessitating secondary breakage and in some cases completely unfragmented sections of a blast resulting in low dragline diggability were encountered in the interburden blast. Twelve blasts were therefore closely monitored and dragline productivity evaluated. The ultimate aim was to improve the overall blasting performance and hence increase dragline productivity. Three areas were in focus; fragmentation assessment, dragline productivity assessment and cost analysis. The studies indicated unsatisfactory explosive and initiation performance, problematic blast design and questionable operators performance. It is established that dragline cost account for 60% of the total mining cost whereas the drilling and blasting cost account for the remaining 40% and that improvement in dragline productivity results in automatic cost saving.

Jan 1, 1996

By S Lukovic, Robert Briton, Calvin J. Konya

Investigators have reported that charges which are decoupled from the borehole wall produce different fragmentation then those which are fully coupled. The difference in effect could be as a result of energy doss during transmission across the air gap or it could be due to the change in detonation characteristics of the explosive as a result of the change in confinement on the charge during detonation. In order to better understand the phenomena of decoupling, a research project was conducted at the United States Bureau of Mines Station, near Pittsburgh, Pennsylvania. It was decided to use shock and bubble energy tests along with simultaneous velocity measurement to determine the mechanics of decoupling and energy transmission. Two explosives were selected for the test, one dynamite and one water gel. Test results indicated that decoupling could both boost the total energy output of the explosive and that further decoupling would drop the energy output.

Jan 1, 1987

By Fred C. Drury

The introduction and growth of modern chemical explosives based upon prilled ammonium nitrate has been the most significant development in the explosives industry during the 20th century. These modern chemical explosives have been of incalculable value to our society. Their use has permitted a reduction of blasting costs, improved safety, and the development of new resource sources which would not have been accessible without this new technology.

Jan 1, 1980

By Otto E. Jr Crenwelge, Timothy A. Peterson

We have developed a site-specific method for analysis, prediction, and control of ground vibrations induced by overburden blasting operations in surface coal mines. Field tests conducted at R&F Coal Company have verified our approach for obtaining signatures of the overburden vibration characteristics at locations of interest near the mine, selecting the optimum excitation frequency for minimizing vibrations, measuring and synthesizing multiple-charge excitation signals for minimizing vibration amplitude and duration and controlling frequency, accurately predicting the multiple-charge vibration response in both the time and frequency domains, and accurately controlling the blast detonation to achieve the predicted vibration control. Initial field studies also indicate that by minimizing the vibrational energy radiated from the blast zone, and by optimizing the number of charges detonated per delay period as allowed by this technique, more effective use of the explosive energy is obtained within the blast zone itself for improving overburden fragmentation, swell, and cast. In all of the phases of this technique, including actual blast detonation, personal computer hardware and software have been verified for use in either field or office environments.

Jan 1, 1986

By B Mohanty

Several parameters such as, Energy, Strength, Brisance, Impulse, and Bubble Energy, are in common use in the explosives industry today to rate commercial explosives in terms of blasting performance. However, this multiplicity of terms, their frequent interchange and their purported one-to-one correlation with expected performance have given rise to a considerable amount of confusion, and have often resulted in unrealistic rating of explosives. In this paper, various theoretical and experimental methods of estimating energy and performance of explosives are discussed and their relative merits examined. These methods include, Computer Code Calculations, Cylinder Test, Trauzl Test, Ballistic Mortar Test, Underwater Test and Model-scale blasting. It is shown, in the light of actual blasting process, that such measures cannot be considered accurate indicators of expected blasting performance as the properties of rock to be blasted are either totally ignored or only partially accounted for in these methods. It is also shown that no single technique alone among those currently employed by the explosives industry can lead to realistic rating of explosives in terms of expected blast results. The need for the adoption of a two-tier rating system, one based on chemical potential "energy", and the other based on blasting "performance" is proposed, and specific approaches to achieve this objective are outlined.

Jan 1, 1981

By Charles Dowding, Cathrine Aimone-Martin

This article summarizes an investigation of the structural response of a brick façade home in New Mexico. The subject Ricter residence was located some 1100 to 1400 ft away from an aggregate quarry, and was subjected to a maximum peak particle velocity and air blast over pressure of 0.29 ips and 122 dB, respectively. Superstructure (corner) and mid-wall responses to blasting and human induced activities were measured. An existing exterior crack in the brick work was instrumented to measure crack width response to blasting, human induced activities, and environmentally induced changes in temperature and humidity. Crack and structure response data were correlated with ground velocity and airblast excitations. Amplification of ground motions at the upper structure were calculated and compared with values for typical wood frame structures. The natural frequency and damping characteristics of the structure were determined to compare with measured amplification values. Wall strains produced by bending and inplane tension strains were computed from upper corner structure response and compared to failure strains for drywall and brick veneer. Calculated strains were found to be far lower than those required to crack brick and environmentally induced crack response was found to be far greater than that caused by blast induced ground motion or airblast overpressures

Jan 1, 2005

By M. Oguz Ozkazanc, Gulsev Uyar Aldas

Because of its safety, being easy to handle, relatively inexpensive and containing a lot of energy, ANFO is the most popular and widely used explosive in Turkey as well as other countries in the world. According to change dated May 14th 1999 on the regulation 87/12028 related with explosives, blasters are not allowed to mix ammonium nitrate and fuel oil in the tield to make ANFO. Instead of this, they have been forced to use the ready ANFO prepared by explosive producer firms. As a result of this obligation, the use of technical nitrate for agricultural purpose and mixing AN and fuel oil in unsuitable conditions have been prevented. Indeed, wrong mixture means waste of energy and money.

Jan 1, 2001

By Brian Wingfield, Rick Givens, Greg Williams

Many technological advancements have been made in explosive products and applications over the last 15 years resulting in productivity and cost gains. However, the applications of total energy (engine horsepower) in the majority of rotary drilling technology, has remained virtually unchanged over that period. While advancements have been made in components, efficiency, and types of hydraulic systems used on drills, the application of current hydraulic technology to improve drilling productivity has not been interactive with end users. This paper will investigate how traditional design assumptions, regarding typical application of horsepower in current rotary drill systems, can actually limit productivity.

Jan 1, 1996

By Orica Peru, Pedro Lozada

Maintaining a continuous mining process during thunderstorms is one of the primary challenges in Peru's open-pit mines. Safety protocols necessitate the establishment of exclusion zones to minimize the risks of unplanned detonations. During such conditions, loading and hauling equipment must be relocated or, in the worst case, halted, directly affecting productivity (t/h). Implementing a wireless initiation system mitigates the risk of unplanned detonations during electrical storms by eliminating the use of electrical cables that are susceptible to electrical discharge. This study documents the implementation of this system in a copper mine located over 3,500 meters above sea level in Peru, where electrical storms between December and March necessitate modifications to blasting schedules and limit the number of drills fired per event. Through a test using wireless detonators, a key performance indicator (KPI) was established to ensure safe and continuous operation during thunderstorms. The results were significant: 20 blasts were successfully executed, firing approximately 5,000 holes and moving around 10 million tons of material, all without safety incidents or critical operational deviations, achieving zero misfires and no scheduled blast suspensions. Shovels SH001 (ore) and SH002 (waste) continued to operate together for an additional 100 hours continuously during thunderstorms, generating a potential saving of USD 3.3 million by continuously sending ore to the plant during the testing period under stormy conditions. Additionally, the blasting initiation time was reduced by 25%, eliminating two activities that involved the use of surface connection cables. This reduction led to over 150 hours of decreased personnel exposure to interactions with vehicles and environmental hazards such as dust and noise. Furthermore, the number of holes fired in a single event increased by 50%, enhancing the blast tonnage capacity and reducing equipment stops due to evacuation and reentry from two to one.

Jan 21, 2025

By Jaak J. K Daemen, Carol Geertson

A portion of a tailings impoundment may need to be removed with the expansion of an open-pit mine in northeastern Nevada. The tailings are saturated and consist of fine silty soil. During the removal of the tailings, they would have no support structure and vibrations induced by blasting in the pit could lead to slope failures.

Jan 1, 1998

By Bharat B. Dhar, M D. Nabinllah, A J. Prakash

The study is an approach made in simulating air overpressures induced by surface blasting from those produced during gallery blasting in the laboratory, and experiments conducted on a portable window with a view to establish the sound pressure Level (SPL) for cracking of window glasspanes.

Jan 1, 1994

By Dave I. McGregor

The Multiple Raise Round Blasting Technique (MRRBT) is a safe, efficient, cost effective method of blasting thee will use existing mine personnel. The MRRBT, developed from the conventional 'drop raise method' style of blasting, can be used for most raise mining applications. Current results using MRRBT indicate no upper limit for the maximum length that a raise can be blasted.

Jan 1, 1994

By D. Scott Scovira, Rick Webber

The Iron Ore Company of Canada [IOC] is a global leader in Arctic mining applications, and the blasting crew have something to be very proud of. On Wednesday 21 Dec 2005 at 3:28 PM the largest single bench blast in the company history was detonated. The successful firing of this 5.0 million tonne [5.5 million ton] blast surpassed the previous company record of 3.8 million tonnes [4.18 million ton].

Jan 1, 2008

By Gordon Matheson, Bill Yancey, David K. Miller

"Current regulatory limits for blast vibration and airblast control in Virginia do not specifically addressunderwater explosive testing. Underwater detonation of explosives generates an initial shock wave and a gas bubble. The gas bubble expands and collapses several times before reaching the water surface. This expansion and collapse of the gas bubble as it rises to the surface is called a “bubble pulse”. The bubble pulse generates low frequency vibrations that have the most potential for damaging structures and causing blasting complaints even below damage levels."

Jan 1, 1999

By Harry Verakis, Thomas Lobb

A great deal of information has been presented and published on the danger from flyrock created from blasting operations. The creation of flyrock is not specific to any one blasting operation. Flyrock is certainly not a stranger to blasting operations conducted in the mining industry and its effects are well known. Flyrock is among the leading causes of mine blasting injuries. Awareness and diligence is the message that must continue to be stressed and followed to reduce the potential for creating flyrock from blasting operations and to reduce the hazard it presents. A recent accident that resulted in a serious injury at a limestone mine in Pennsylvania bears witness to the ever-present danger of flyrock created from blasting operations.

Jan 1, 2007

By Lon D. Santis

The Code of Federal Regulations Title 30, Parts 56, 57, 75, and 77 require that detonators and explosives be separated by four inches of hardwood or equivalents when transported together in mines. This standard was developed to protect the explosives from initiation by the more sensitive detonators. The research reported here is an attempt to quantify the fire protection offered by four inches of red oak and other materials. Boxes with a volume of 6.75 cubic feet were made from four-inch thick rough green oak (RGO), two-inch thick RGO plied, two-inch thick #1 common (dried) red oak plied, and a metal/plywood composite. These and boxes meeting the Institute of Makers of Explosives' (IME) Safety Library Publication No. 22 were tested in bonfires. The boxes were instrumented with thermocouples, filled with detonators, and placed over a kerosene fire imparting about 16 kilowatts per square meter heat flux for up to 3 hours.

Jan 1, 1997