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By David Harrison, Edward J. Walter, Meitra Ferek

Agreat tool in the prevention of blasting complaints and subsequent damage claims. In today’s highly competitive industry, we are always looking for ways to become more cost effective. This article investigates the importance of pre-blast surveys-not just for regulatory compliance, but as an overall long term cost cutting and public relations tool.

Jan 1, 1995

By N/A N/A

Aw a rd winners from the University of MissouriRolla. Back row from left: Seok Bin Lim, Chris B o l l i n g e r, Adam Kre s l e r, Scott Geer, Joseph Cohn, and James (Buck) Hawkins; Front ro w f rom left: Dr. Worsey, Trish Robertson, and Fio G i a n a

Jan 1, 2004

By Steve Kane

Lightning is a very real problem in the surface mining industry. Today, as adverse market conditions continue to influence the surface coal industry, it has become necessary that all functions of the surface mining process become as efficient as possible. High production with reduced manpower is the winning combination of staying competitive in the market place. We at AMAX Coal are committed to staying in the coal business, but we have always been committed to providing a safe work environment for our people and will continue to do so in the future. Approximately two years ago, our Midwest mines installed state of the art lightning detection and warning systems at our mines. This paper will cover its application at Delta Mine; the benefits and problems encountered, and the impact this system has had on Delta Mine.

Jan 1, 1992

By Jose Pineda, Abraham Lindo

The Panama Metro System’s Network expansion involves excavating a launching shaft for a tunnel boring machine (TBM) to traverse beneath the Panama Canal. The blasting needed for this shaft construction poses significant challenges due to the presence of concrete walls encircling the excavation. These walls must remain intact throughout construction and the tunnel's future operation. This case study is focused on devising and implementing safe blasting techniques crucial for the shaft's construction, ensuring the preservation of surrounding concrete walls and project equipment. As the interest was potential damage to the concrete walls, an appropriate vibration threshold for this project was also required as an alternative to the traditional U.S. Bureau of Mining RI-8507 limit (USBM RI8507). Blast modeling software was employed to conduct a series of blasting simulations. Parameters like hole diameter, spacing, depth, explosive type, and initiation methods were varied to evaluate their potential effects on wall stability and damage risk. The simulations revealed that smaller diameter holes and reduced spacing between blast holes would effectively mitigate the risk of wall instability. Additionally, utilizing electronic delay detonators and carefully planning the blast hole detonation sequence proved critical in minimizing potential damage. Executing these blasts in the field presented unique challenges, including strict charge per delay thresholds and logistical constraints. Consequently, continuous adjustments to blasting parameters were made and comparative result analysis. Beyond providing a safe blasting strategy for the TBM launching shaft, this study offers invaluable insights into adapting blasting designs to align with environmental and structural safety standards. These findings hold great potential to shape guidelines for analogous sensitive construction projects. They underscore the importance of leveraging prior research as a reference point, engaging with project designers and local authorities, and continually conducting testing and adjustments to ensure project success.

Jan 21, 2025

By William Adamson

Precise and data driven methods of predicting and modelling blast induced vibration intensity are created and applied under field conditions on a routine basis today. These models are fed with controlled field measurements of vibration pulses generated by controlled charges under known geometric conditions. With such models blasting and geomechanical engineers can estimate vibration intensity at established critical points in mine bench geometry (surface mining) as well as within semi-permanent crown and rib pillars (in underground mining).Damage to bench walls and destabilization of large-scale geomechanical structures can be partially attributed to high intensity blast induced stresses on the rock mass and structures that define important features such as safety catch berms and haul roads. In the underground environment, weakening of critical pillars in block caving or Long Hole Open Stoping(LHOS) operations may lead to ore sterilisation. Blast vibration intensity can be linked with physical alteration in critical rock mass volumes within themine. Often the potential for vibration damage is estimated by the calculation of a critical value of vibration intensity, derived from a consideration of laboratory measured rock matrix properties. Efforts to confirm the accuracy of these estimates of critical vibration level include post blast excavation photography as well as the visual examination of rock mass, pre-and post-blast, using video camera observation of the walls of purpose drilled observation holes. These methods clearly indicate a change in fracture state due to the blast induced vibration, however further modelling of geomechanical stability will benefit if seismic measurement data can be interpreted in terms of geomechanically relevant strength parameters. This paper describes some of the results of previously unpublished research studies conducted in underground operations in Chile and Australia, where cross-hole seismic measurement profiles were interpreted in terms of dynamic modulus. This work dates from a period between 1987 and 1990 and the Author suggests that 30 years on, applying modern day technology, instrumentation and modelling methods, more meaningful, practical and applicable results may be obtained.

By Thierry Bernard

To be able to precisely predict the result of a mine blast before pressing the button is a goal for many blasters due to the environmental and economic constraints of our century. Based on the fundamental fracturing of the mechanism of rocks by explosives, the most recent research in digital modeling, the power of present computers, and the possibilities offered by drones, we have designed a realistic digital 3D simulation model for mine blasts

Feb 1, 2020

By William R. Adamson

This paper describes some of the results of previously unpublished research studies conducted in underground operations in Chile and Australia, where cross-hole seismic measurement profiles were interpreted in terms of dynamic modulus. This work dates from a period between 1987 and 1990 and the Author suggests that 30 years on, applying modern day technology, instrumentation and modelling methods, more meaningful, practical and applicable results may be obtained.

Feb 1, 2020

By Ed Clah, Catherine Aimone-Martin

The vibration response of a 30 in. diameter high-pressure (845 psi) natural gas pipeline to 11 coal mine blasts was measured. The X-52 steel pipeline was buried 7 ft. below the ground surface. Ground and pipeline motions in terms of velocities were recorded on the pipeline, in the ground adjacent to the pipeline, and near the ground surface directly above the pipeline. These data were used to estimate the maximum stresses and strains in the pipeline occurring during the blasts. Pipeline standoff distances varied from 264 ft. to 3720 ft. Two blast hole layouts and timing schemes were used. One represented highly confined blasts to limit movement of the shot overburden that generated high ground motions at the pipeline. The second represented patterns that provided greater relief and lower the ground velocities at the pipeline.

Jan 1, 2003

By A. Karadogan, G. Tuncer, A. Kahriman

Determination of optimal blast parameters have been the priority act for blasters on the field due to financial and technical properties of the operation. Therefore many researchs were done to establish a general formula for many years. These intends could reach some empirical and numerical design frames consisting the rock, geology and explosives properties. Blasting parameters have to be adjusted according to the desired fragmentation rate especially on the mines where particle size distrubition after blasting has a great importance. Therefore the blast designs have to be evaluated considering the particle size distribution after the blasts. The Kuz-Ram model which was modified by Cunningham is one of the tools for estimating the particle size. Although it doesn’t give an accurate result, it can be very succesful on modifying the blasting design parameters by establishing a back correlation between the blasting parameters and the exact particle size distribution results which can be easily achieved by digital image processing system. Within the scope of this study, the particle size distribution after blasting was assessed by Split-Desktop digital image processing system and bench blasting parameters were studied considering the desired particle size distribution at Espey colemanite mine using Kuz-Ram and digital image processing system combination to determine the specific blasting parameters for this site.

Jan 1, 2005

By R M. Bhatawdekar, A I. Theresraj, H S. Venkatesh

Wadi Limestone Quarry is one of the largest captive mines of Associated Cement Companies Ltd, India. The mine management wanted to extend the excavation as close to the plant as possible for maximum exploitation of the deposit. The National Institute of Rock Mechanics and the management of Wadi Limestone Quarry carried out comprehensive investigations to evolve a methodology to control vibration and flyrock within safe limits.

Jan 1, 1999

By S. Gajardo, E. Valdés Guerra

Together with Sociedad Punta del Cobre S.A. (Pucobre) and Orica, we are carrying out a study of alternatives for methodology of excavation in Slot Up Raises from actually built with Blind Hole (BH) to drilling and blasting (DB) methodology. The study is part of the permanent search for innovation, the use of technology and the reduction of mine operation costs. This application aims to optimize the Sub Level Stoping method, which has historically been exploited at Pucobre. Using a new variant of the method “Open Stoping”, through the initial development of ascending blind raises using a pilot drilling of a bore hole, with the objective of eliminating the upper level in order to excavate the free face opening. This industrial test aims to replace the mechanized BH Up Raise of 1.5m (4.9 ft.) in diameter and 30m (98.4 ft.) high, with a Up Slot Raise considering two separate blasting events, using different technological enablers, as detailed below: accuracy drilling with relief holes of 254mm (10 in.) diameter, high viscosity bulk emulsion, wireless initiation system and high-strength injectable bulk resin. Considering the importance of the success of this application, a DB diagram was defined to allow the opening of the up raise in two blasting events, separated by intermediate stemming deck located at the same level at a height of 15m (49.2 ft.) from the collar, using high-strength injectable resin. The first blasting event considers the first section from the collar to the first 15m (49.2 ft.), using wired electronic initiation that is detonated on the first day. A second event blasts the section from 16.5 to 30m (54.1 to 98.4 ft.), using a wireless initiation system, as, it has no physical connection, is blasted on the second day after the extraction of the material resulting from the first event. For greater precision, the design of the explosive charge configuration and initiation sequence is made, adjusted to the measurements of trajectory deviations of the actual ground drilling and is also considered for the control of the explosive charge configuration with high viscosity bulk emulsion. This application improves the profitability of the mining business by generating savings through the change of Blind Hole methodology, estimating a savings of more than 75% per Up Slot Raise

Jan 1, 2024

By Ken Eltschlager, J Silva Castro, J. M. Hoffman, Braden Lusk

This case study focuses on analysis of sounds inside a house induced by blasts as result of surface mining coal in West Virginia and how to better communicate technical information to the public. The field study included a house wide vibration and sound monitoring system installed in a home which was subjected to blasts at varied distances and direction. The structure response was separated into ground vibration and airblast induced movement due to the differences in their times of arrival. This signal was then compared to the sounds recorded to determine which component of blast (ground vibration or airblast) induced the maximum sound. Findings shows that blasts at distances less than 762 meters (2,500 feet) had maximum sound responses from both ground vibration and airblast. While for blasts beyond this distance the maximum sound response was caused by ground vibration without exception. The kitchen generally created the most sound. The second phase of the study was to gauge the public’s response or preference to technical information. Three hundred and forty eight (348) telephone surveys were conducted in Logan and Boone counties West Virginia. Based on the survey, the public prefers units of pounds per square inch (psi) for airblast and millimeters of displacement for ground vibration. Ultimately a public relations plan was developed based on the results.

Jan 1, 2012

By A. Andrades, E. Arias, Y. Pizarro, J. Alarcón

Division Ministro Hales - Codelco (DMH) is located at 2600 meters above sea level, 10 km north of the city of Calama, Antofagasta region, Chile. In operation since 2010, it corresponds to a porphyry copper deposit that is exploited by the open pit mining method. The ore is mainly composed of sulfides, which is concentrated by comminution processes such as crushing, SAG milling and ball milling to liberate the mineral particles, and then separated from the waste (concentrate) in flotation stages, including a concentrate regrinding stage. Reports from the DMH processing plant area have identified a decrease in fine copper recovery, with the first hypothesis being the high percentage of ultrafine particles (% <45µm) in the flotation feed. Due to the above, DMH & Orica decided to carry out activities to identify the controllable variables that can impact the generation of low size particles in ore and adjust them to reduce the percentage of fine material generation, with special focus on the Drilling and Blasting processes. Based on the data provided by DMH, we evaluated what could be integrated to make an analysis. The different attributes associated with the ore and their effect on copper recovery were evaluated. In parallel, at the mine, a fragmentation measurement campaign was carried out at the loading faces and granulometric analysis of the drill cuttings. Once the correlations between the attributes and copper recovery were identified, hypotheses were established and reviewed with the Drilling & Blasting, Geotechnical, Geology and Process Plant areas. With the validations of the hypotheses and the results of the in-mine (cutting) measurements, we proceeded to review the criteria for the classification of Blastable Geotechnical Units and their associated D&B designs. Using software and the Crush Zone Model (CZM) tool, which considers rock and rock mass parameters, scenarios for various D&B design proposals were simulated with the objective of reducing the generation of ultrafine particles from the blasting process. Next steps include trial blasting with the D&B design recommendations, which will require follow-up to the flotation process to identify the impact on the reduction of ultrafine material from blasting.

Jan 1, 2024

By Harry Verakis

Flyrock is the second leading cause of all blasting related injuries in surface coal, metal and nonmetal mining operations. It is also a primary cause of property damage, monetary losses and “near misses.” For the period 1978 to 2008 flyrock accounted for 11.6 percent of all blasting-related injuries in surface coal, metal, and nonmetal mines. A large amount of published material has been published on the safety hazard of flyrock, on ways to predict how far rock will travel from a blast, as well as ways to protect mine personnel and neighbors from flyrock. However, flyrock incidents continue to occur resulting in fatalities and “near misses” that could have caused fatalities. It was only good fortune in some instances that no one was in the mine's parking lot or other unprotected area when flyrock rained down or in harm’s way when a large rock punched a hole in the roof of a building or other structure.

Jan 1, 2011

By Lon Santis

This paper analyzes 110 serious accidents that occurred during the use of commercial explosives in mining, construction, and other industries since 1992. Data from the Mine Safety and Health Administration (MSHA), the Institute of Makers of Explosives (IME) members’ reports, and media reports were used. Only accidents that resulted in a fatality, significant lost work time, or injury to the public were considered in this analysis. The accident data were analyzed for trends in frequency, type of industry, cause, type of individual harmed, and geographical region. Although the data showed that explosives accidents are decreasing in frequency, still, 29 people were killed and 134 injured. Eightyfive of the accidents occurred in mining, 17 occurred in construction, and 8 occurred in other industries including oil recovery, seismic exploration, agriculture, logging, boiler cleaning, and avalanche blasting. As other studies have shown, flyrock and failure of blast area security caused over half of the accidents. Mishandling, misfires, or fumes caused just over one-third of the accidents. Lightning and drilling into explosives were responsible for the remainder of accidents.

Jan 1, 2003

By Robert Hopler

RBH Note: At the time of this price list the handwriting was already on the wall regarding the ultimate breakup of the company under the Sherman Anti-Trust Act. The brand names Atlas and Hercules, noted on page 3 of this pricelist, would become the names of the new companies created from du Pont.

Jan 1, 2012

By Wayne A. Charlie

An experimental test program being conducted at Colorado State University and involves the study of the behavior of water saturated sands under shock and explosive loadings. The study is being conducted to evaluate potential blast induced changes in dynamic soil properties, soil shear strength loss (liquefaction) and densification of water saturated sands under single and multishock loadings. This paper presents testing and measurement objectives, and the equipment and instrumentation developed to load, measure, record and analyze the transient and long term soil behavior. The laboratory shock facility is capable of generating multi-shock pulses with milli-second rise time, peak stress amplitudes of up to 35,000 KPa (5000 psi), peak particle velocity of 5000 cm/set and peak acceleration of 10,000 g. The field explosive facility subjects saturated soil to controlled explosive loadings. Of major interest is the soil strain and water pressure, both during and after the passage of the stress wave, as a function of peak particle velocity, peak strain, loading rate, soil density, initial confining stress and the number of loadings. Based on data obtained to date, soil densification is due to consolidation following liquefaction.

Jan 1, 1991

By Cceliksirt, V Erkan

This computer program has been developed under the field conditions for use in control of surface drilling-blasting operations. This paper outlines the relevance of fragmentation to quarrying, open pit mining or road cutting and key features and operating principles of the software (DelPat for Windows 95).

Jan 1, 1998

By David Leidel, James Stuart

The 50 ohm resistorized electric detonator is commonly used in the oilfield for initiation of wireline conveyed perforating guns and other downhole explosive tools. This type of electric detonator provides some degree of safety above that of the conventional one ohm electric detonator, since a higher current level is required to initiate the device. In order to obtain the necessary data to develop safe distance tables from RF sources for the 50 ohm electric detonator, laboratory tests were conducted to determine the detonator’s “no-fire” current, AC impedance, and its susceptibility to ESD. The results were surprising as two types of failure modes were observed. The “no-fire’ current levels determined from Langlie “One-Shot” Test Methods were determined for the devices tested providing values for the 0.999 probability “no-fire” power level at a 95% confidence level. This data will serve as the basis for sets of safe distance tables from RF sources that will appear in the forthcoming edition of the Institute of Makers of Explosives Safety Library Publication 20, “Safety Guide for the Prevention of Radio Frequency Radiation Hazards in the Use of Commercial Electric Detonators, (Blasting Caps)”.

Jan 1, 2010

By Norm Tienkamp, Normand Martineau

Through the normal course of operation, mine operators are living situations where blast results need to be measured. It becomes the supervisory group responsibility to select evaluation parameters with appropriated and available technics. In Mine Selbaie's case, we have retain the following parameters: rock fragmentation, oversize fragments, rock pile movement, grade rupture.

Jan 1, 1996