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By Rolf Schillinger

Blasting activities on the surface or underground necessarily involve the most sensitive aspect of environment remediation, human response or annoyance. Such effects are unavoidably characteristic of those activities. For this reason, blasting activities are governed by law and official regulations under surveillance of authorities, where companies and explosives engineers have to proceed within proper limits. Subject of the paper is a practical way of handling some necessary vibration standards being focused on blasting activities. The paper is based on the German Standard DIN 4150, Part 1 - 3, “Vibration in buildings”, Part 1: “Prediction of vibration parameters”, June 2001, Part 2: “Effects on persons in buildings”, June 1999 and Part 3: “Effects on structures”, February 1999.

Jan 1, 2006

By Joshua Taylor Drake

This report answers specific questions concerning underwater blasting considerations, and blasting safety. The blasting considerations discussed consist of basic blasting principles, and new variables to be accounted for. Blasting safety will include the safety of personnel and structures. The environmental considerations will also be discussed with mitigation methods. To be most effective, this document requires the reader to be familiar with key fundamentals of explosive engineering. In order for a blasting professional to benefit from this report, the following questions will be asked:

Jan 1, 2015

By Alastair C. Torrance

"A brief review of the Australian mining industry is given followed by a more detailed treatment of a study of the influence of primer Size on explosive performance. This is based on a joint research programme conducted by BHP Central Research Laboratories and Dyno Wesfarmers Ltd and examined the effect of the size of cast primers on the run up and steady state detonation velocitiesof ammonium nitrate based explosives as a function of blasthole diameter. The field trials examined a numter of the Dynamo 'Westfarmers HDF series of primers in conjunction with ANFO, emulsion and watergel explosives. Results indicate that the iun up velocity of 187 mm diameter ANFO charges is negligible using cast primers as small as 150g. However, emulsion and watergel explosives did exhibit run up in both 187 and 3:1mm diameter blastholes, independent of the size of primer. This could last from 7 to 10 blashole diameters"

Jan 1, 1991

By Gregory B. Poole

As part of a $3.5 billion program to improve the antiquated waste water system in the city of Atlanta, the Nancy Creek Tunnel is being constructed across the northwest portion of the city. This tunnel is over eight miles long and is being constructed using Tunnel Boring Machines (TBM) for the majority of the tunnel and conventional drilling and blasting for three shafts, starter and tail tunnels and four connecting tunnels, totaling 2400 feet in length. An extensive public relations program was developed for this project. A group effort by the owner, engineer and contractor produced a public relations program that both informed and educated the public of the anticipated perceptions and effects of the blasting and TBM activities.

Jan 1, 2005

By D Frantzos, J J. Cotter, H Tammemagi, J B. Codrington, J Kaasalainen, A C. Webster

"Exploshres Technologies International (ED) is developing an instrument called ROCSCAN which isplanned to have broad application in both blasting and rock mechanics. The purpose of this paper is to outllne the background that has led to the development of ROCSCAN, describe its objectives and to present a progress report on the work to date. Some of the potential applications of ROCSCAN will also be reviewed."

Jan 1, 1989

By C. M. Badeen, J. Paige, W. Evans, L. McCauley, A. Caddies, I. Alilovic, R. Turcotte, C. O. Lyogun, C. Bonner

Gear pumps are very commonly used for the pumping of AN-water based emulsion products for both handling and blast loading applications. The potential major hazardous problems likely to be encountered with these pumps are: (i) high probability of friction; (ii) possibility of product confinement in the area of the bushings; (iii); high bearing failure rate; (iv) pump running dry; (v) presence of foreign material; (vi) deadheading of pump; (vii) delamination of elastomer from steel gears. Of all these possible scenarios, the no-flow situations where the pump is running dry or deadheaded have always been recognized as the most serious ones.

Jan 1, 2015

By Laura Bastemante, Bruce Vandenberg, Fred Huettig

Recent advances in solid-state, field portable, fast framing video camera systems and PC based frame capture hardware now allow blast imaging up to loo0 frames per second. Up to 8 seconds of data can be stored directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the KineView 1256P system and compare these with the analogous aspects of film based cameras.

Jan 1, 1997

By Michael S. Wieland

"Toxic fumes cause fatal andnonfatal incidents in underground mining, where the working environment tends to trap the fumes, hindering the restoration of non-harmful conditions. Workers can underestimate the residual fume toxicity and return to the work site too quickly. The toxic fumes from charge explosions depend upon a number things: formulation ingredients, mixture uniformity, water resistance, hole contaminates, rock hardness, and dust interactions. Transitory hole-to-hole waves can cause partial desensitization, ruin the reaction kinetics, and worsen the fume toxicity.Traditionally the toxic fume hazard for a candidate explosive is resolved from a requisite tally of fume components. The resolution starts with the fume spectrum, a tabulation of specie concentrations, transformed to standard reference conditions and readjusted to remove the air dilution. The resultant influence, which is referred to as relative fume toxicity RFT, is deduced by a formula rule with some chosen constants and the requisite concentrations. The RFT result is normally compared to an RFT criterion that represents the worst-case (maximum) tolerable fume toxicity, as stipulated by regulations or otherwise."

Jan 1, 1997

By Michael Wieland

The resolving capacity of the thermodynamic work-principal model has been seriously refined over its twelve year history, so a review of the innovations, wrong turns and their rectification is warranted to help future researchers. The work-principal model rests upon the four laws of thermodynamics that drive the universe and relatively few other assumptions: like the removing and imposing of constraints on the quasi-potential to yield trapped minimum key-states that represent the wanted process. The formative research was concerned with the role of ingredient changes, the removal of booster influence and the quench temperature with which to reckon toxic fumes. The transfer of reaction-zone energy as work upon the surrounding rock/water/fixture was not fully rationalized until the notion of reversed-inertial pressure was formulated and determined (for water) with underwater trinitrotoluene (TNT) shots. The rock-water-jelly model incorporated that term into its dynamic pressure formula as a way to represent rock blasts or underwater shots, while the zone of reaction gases remained trapped. The real irreversible thermodynamic process, which yielded the total expansion work, was later complemented with a wholly reversible imaginary process, to form a closed thermodynamic loop, with a remarkable consequence – the determination of the theoretical heave and hence, the undissipated-shock by difference from the total work. With the wholly developed model, it was recently possible to quantify the time retardation of reaction chemistry for non-molecular (mining) explosives, as compared to the rather negligible time-retardation found for the molecular (military) explosives in underwater tests.

Jan 1, 2009

By Wayne Rogers, Kell Monro, Arthur Pacunana

The Phu Kham Copper-Gold Operation (PKM) is a large-scale open pit mine located in northern Laos. It was developed and is operated by Phu Bia Mining Limited (PBM) a Lao-registered subsidiary company of Australian incorporated, PanAust Limited. Production commenced at Phu Kham in 2008. Since the second half of 2016, there has been a significant increase in ore hardness and this has negatively impacted the PKM concentrator and resulted in lower SAG mill throughput rates. Over the remaining life of mine, the changing ore body and increase in ore hardness is forecast to continue as the pit deepens and the availability of softer blending ores reduce. To manage this risk, PKM initiated a Hard Ores Management Program to determine the most effective way to improve the mill throughput of harder ores. This involved conducting a number of innovative and process control driven blasting trials to optimize run-of-mine (ROM) fragmentation and other blasting outcomes. From 2016 to 2017, the performance of high powder factor blasting, electronic detonators and fast timing, high velocity of detonation (VOD) explosives, double-priming, and deck blasting, were individually and systematically assessed. The success of each blasting trial was then based on a ‘value for money’ criteria. This criteria is a cost / benefit analysis that weighed-up the additional cost to implement the trial against the measured improvement in mill throughput. Electronic and high VOD 90:10 emulsion:ANFO blasts were determined to have the best value for money, achieving an increase in mill throughput of 54% compared to baseline. This paper discusses how the implementation of an innovative and process control driven blasting trial methodology was able to successfully manage the hard ore challenges at PKM. In addition, this success was achieved without any major cost implications, safety incidents or process plant set-backs.

Jan 1, 2018

By Ajoy K. Singh, B Mohanty, P K. Singh

A study was conducted to investigate the damage potential to underground multiseam openings caused due to vibration generated by open-pit coal mine blasting. The objective was to recommend optimal explosives weight per delay to be detonated in open-pit blasts to ensure the safety and stability of underground openings. Sixteen blasts with varying charge weights and initiation sequences were conducted at Samleshawari open-pit mine and eighty four blast vibration data were recorded in the Hingir Rampur underground colliery in India. Analysis of vibration data showed that roof of the underground openings vibrated with much higher amplitudes compared to those in pillars and floors. The amplifications of vibration in the roof at the junction were upto 4.3 times the pillar vibration. It was observed that coal chips detached from roof when the peak particle velocity reached 131 mm/s or higher. The vibration magnitude recorded was higher in upper-seam openings than in belowseam openings. Rapid attenuation of vibration was recorded in below-seam openings at similar locations. Appropriate particle velocity-charge weight-distance equations were established to calculate the safe explosive weight per delay to be detonated in open-pit mine for the safety of multi-seams workings of underground mine. The support for the galleries and junctions were further modified for the working seams to ensure greater safety.

Jan 1, 2011

By S. Kevin McNeil, William Joa, Catherine Johnson, S. Omar Garcia

The geometry of an explosive is known to have a fundamental effect on the resulting shock wave propagation. Typically researchers use a spherical or hemispherical geometry in order to simplify the shock wave so that resultant overpressure and impulse are uniform in all directions. The goal of this research is to understand the overpressure characteristics from a sheet explosive, a geometry often utilized for breeching in the military. In training alone, soldiers can be exposed to several tests per day, which may be contributing to the prevalence of blast induced mild traumatic brain injuries. Using PCB pressure transducers and high speed video, it was found that as the angle departed from normal (perpendicular) to the face of the sheet explosive, the over pressure decreased significantly. When in line with the plane, a decrease of over pressure by as much as 20% was observed. Time of arrival was roughly 20% faster directly in front of the charge with a pressure amplification of 46% relative to a spherical baseline charge of the same mass. This testing may reveal a more complete relationship between the pressure and angle from the explosive that could have applications for military and law enforcement with respect to best practices on blaster location for reduced over pressure exposure.

Jan 1, 2019

By Braden T. Lusk, Rex A. Meyr, Kyle A. Perry

Following three major mining accidents in 2006, the MINER Act of 2006 was enacted by MSHA and required every underground coal mine to install refuge alternatives to help prevent future fatalities of trapped miners in the event of a disaster. A polycarbonate safe haven wall for use in underground coal mines was designed and modeled using finite element modeling in ANSYS Explicit Dynamics to withstand the MSHA required 15 psi (103.4 kPa) blast loading spanning 200 milliseconds. The successful design was constructed in both half-scale and small scales in the University of Kentucky Explosives Research Team’s (UKERT) explosives driven shock tube. The constructed polycarbonate walls were tested multiple times to determine the walls resistance to blast pressure. The results for each test were analyzed and averaged to create one pressure versus time waveform which was then imported into the finite element program and modeled to compare deflections of each part to that was measured during testing for model validation. This paper summarizes the results.

Jan 1, 2014

By Adam Gray, Emery Gray

State-of-the-art seismographs can be employed to assist the blasting engineer in understanding the propagation of vibration waves generated by blasting. Wave traces and frequency plots are used to adjust shot loading and timing, especially around close or near- field structures. Successful close-in blasting vibration monitoring requires careful consideration of the following: Geophone locations Mounting of geophone both on structures and in the ground Differences between ground motion and structural response This presentation will discuss methods used to control and monitor blast-induced ground and structure motions. Case histories are presented to illustrate seismic monitoring used as a tool to control vibrations and guide the blaster in the design process.

Jan 1, 2005

By Peter Moser, G. Reihholf

Holcim, one of the world's leading suppliers of cement, aggregates and concrete, has set up a few years ago a working group “Quarry” in order to optimize the performance of its central European quarry operations in terms of work safety, environmental standards and economic performance. One of the activities of this working group "Quarry" addresses the subject of blast fragmentation in the quarries. A benchmark study of the blast work in all quarries has shown substantial differences for the various operations in terms of drill& blast costs. Especially big differences were found with respect to the drilling patterns as a function of the borehole diameters and with respect to the utilization of the borehole volume for charging the explosives.

Jan 1, 2006

By Douglas Bartley, Jay Elkin

The state of Pennsylvania was at one time one of the leading coal producing states in the east. However, legislation and industry trends over the last 10 years have adversely affected the amount of bituminous coal mined in Pennsylvania and the whole eastern United States. The application for and approval of a new mining permit is a very costly and arduous task. When a new mining operation is established it is crucial that nothing within the operator’s control causes the operation to stop producing. This paper discusses the action taken by a small mine in Pennsylvania when their blast induced vibrations rose to levels that typically would have resulted in a total mine shut down by the regulatory body governing such operations.

Jan 1, 2003

By John E. Wiegand

"We will attempt to explain the basic workings of a modern seismograph and how the recorded data can be interpreted, not only for determining compliance to the regulations, but also in determining whether or not a seismograph record is accurate and valid. We will discuss some parameters that should be included in all seismographic recordings. We will give examples and use overhead slidesto show examples of both accurate and valid recordings, and tampered and inaccurate seismograph recordings. Much of the information presented will be basic in nature, and will reflect the opinions and personal experiences of the author. We ho'pe the listener will gain valuable information concerning the use and interpretation of seismographic data, as well as find interest and sometimes humor in the examples shown."

Jan 1, 1992

By Sam Kangwa, Thomson Sinkala

In the mining industry, drilling accuracy has a significant effect on the economy of operations. In this paper, results from the Nkana Division of the former Zambia Consolidated Copper Mines are presented. For the stope investigated, it was found that the extra operational costs alone were 462% of the planned costs! Clearly, there is more than good reason to pay attention to drilling of good quality holes.

Jan 1, 2004

By David Miller, James Santoro

Blasting is often required in urbanized areas to allow for economical execution of construction, demolition, and mining. Several examples of operations that require blasting in built up areas include: rock blasting for foundation and utility excavations; surface and underground mining for mineral extraction; and explosives demolition. Although explosives demolition is an engineering discipline, not at all like rock blasting, it still uses explosives for the felling of structures that have outlived their usefulness. Through the use of modem technology and implementation of extra safety precautions, explosives are used safely in congested areas to make the performance of critical work economical and feasible. This paper discusses several precautions required when undertaking various types of rock blasting and explosives demolition in congested areas. It also presents the adverse effects that must be considered when blasting in congested areas. The effects identified include flyrock, vibration and airblast, fumes, and non-elastic (permanent) ground deformations/overbreak. Measures for mitigating and controlling these adverse effects to provide on-site and public safety are presented.

Jan 1, 2000

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