Search Documents

By Pierre De Pasquale, Gilles Jauffret, Ricardo Chavez

"When blasting in quarries or mines, the main source of inconsistent results is directly related to thenon-homogeneous energy distribution through the rock-mass volume. This variation has differentorigins: drilling deviations, geometry differences from one borehole to another (burden, spacing ...),and inherent geological conditions."

Jan 1, 2016

By Alton Dunaway, Kevin Sullivan, Charles Gray, Doug Hall, Kevin Grant, Kelly Thiel, John Paulson, Bruce Leland, Cole Boyd

Beaver (Castor canadensis) are responsible for economic losses exceeding $4 billion over the last 4 decades in the southeastern United States alone. A large portion of these damages occurs to public roads and highways, forests, agricultural resources, and other property from flooding caused by beaver dams. The United States Department of agriculture, Animal Plant Health Inspection Service, Wildlife Services (WS) program is a non-regulatory Federal program directed by Congress to assist resource owners with managing damage caused by wildlife.

Jan 1, 2007

By Rob Farnfield, Ben Williams, Bob Woolley

This paper outlines how drilling safety standards are being driven forward in the United Kingdom’s surface mining and quarrying industry with developments in equipment, procedures and competence.

Jan 1, 2010

By Goran Cirkovic, Zvonimir Ester, Josip Krsnik

During the reconstruction of the motorway Zagreb-Krapina three reinforced concrete bridges were demolished, for their width was not adequate for the new motorway. Demolition of the three bridges was carried out by blasting as duration of the traffic cut on the motorway and the railway was limited to maximally 4 hours. During that period of time the demolished bridges had to be removed. Therefore, very tiny granulation was requested suitable for loading and not endangering the surrounding structures. Before each of three main blasting, trial blasting were carried out including the seismic measurements registering the seismic effects. The nearest residential building was at the distance of less than 30 m from the place of blasting. Additional difficulty was the fact that by each of the three bridges there is a new bridge, with minimal distance between the old and the new bridge being 30 cm. As each of the bridges is of different construction and of various thickness, particular blasting technique has been prepared for each one of the bridges.

Jan 1, 1997

By P A. Lang

Canada is constructing an Underground Research Laboratory as part of a comprehensive program to evaluate the concept of nuclear fuel waste disposal deep in stable rock formations. Careful blasting methods have been designed and quality control procedures have been used for the excavation of the access headings in the underground facilities. This paper describes the work done between 1984 December and 1986 December at the second level, 240 metres below surface.

Jan 1, 1987

By Benjamin Cebrian

Metallurgical testing at Cobre Las Cruces prior to production at the mill was done with overburden gossan. Some of that test gossan was a very fine material, wet by the water conditions at the bottom of the pit. When processed and stored wet at the fines material 3000 tonne (3307 tons) silo, this material cemented in a very unusual manner.

Jan 1, 2010

By Lina Lopez, Jose Sanchidrian, Jean Du Mouza, Essaieb Hamdi

This paper evaluates the actual energy delivered by the explosives used in the fragmentation of rock during blasting vs. the available theoretical explosive energy. The evaluation of the fragmentation energy of the blast is first done. Fragmentation by blasting can be seen as a process in which creation of new surfaces within the rock mass is made by generation of new cracks or extension of pre-existing ones. From this idea, the fragmentation blast efficiency can be assessed as the fraction of the available explosive energy used for creation of new surfaces. The evaluation of new cracks area created by the blast is based on the SIMBLOC methodology and the corresponding fragmentation energy is then obtained by the Griffith theory. Secondly, the amount of energy delivered down to a certain pressure or volume along the detonation product expansion process, given by the useful work, is calculated. This is done by first determining the CJ state of the reacted explosive and subsequently performing an adiabatic expansion calculation of the detonation products from that state. W-Detcom code has been used for the calculations using the BKW equation of state with the Sandia parameter set. The fragmentation energy and the useful work are calculated for blasts performed in two mines in Spain. Multiple regression is applied to the results in order to give an assessment of the better description of the explosive energy .

Jan 1, 2002

Over 45 of the Best Qualified Technical Specialists, Consultants, Engineers, Scientists, Explosive Supplies, Educators and Mine Operators in the World!

Jan 1, 2000

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 D O. Doehring, W A. Charlie, W A. Lewis

The detonation of explosive charges releases large quantities of energy that can produce rock and soil deformations far from the detonation point Extensive data are available on blasting in general and on the performance of certain structures subjected to blast vibrations. However, only limited information is available on the performance of earthfill dams and other hydraulic structures subjected to blasting. The limited data indicate that, whatever the cause, one or several cycles of repeated strains in earthfill dams may cause residual porewater pressure increases. Limiting the peak particle velocity to less than 2.5 cm/s for operating dams constructed of or having foundations consisting of saturated, loose sands or silts and to less than 5 cm/s for other earthfill dams, should keep strains below the threshold strains required for residual porewater pressure increases to occur. Porewater pressures should be monitored throughout a blasting operation, and they should be allowed to dissipate, if necessary, before subsequent charges are detonated.

Jan 1, 1987

By Richard J. Mainiero, Michael S. Wieland, Harry C. Verakis

The Bureau of Mines, U.S. Department of the Interior, has been conducting research on delay blasting in underground coal mines in support of the efforts of Mine Safety and Health Administration (MSHA), U.S. Department of Labor, to revise coal mine blasting regulations. Part of the research centered on developing an understanding of the factors that lead to misfires of permissible explosives. Research was conducted to determine whether frequency of misfires was related to borehole spacing. For a wide variety of permissible explosives, misfires were observed for about 50 X of the holes at 45-cm (18-in) spacing. Misfires were also observed for 60-cm (24-in) spacing, but the frequency of misfires was much lower than observed for the 45-cm (18-in) spacing. The Bureau has recommended that hole spacings of less than 60 cm (24 in) be prohibited.

Jan 1, 1986

By Feng Shuyu Yang Nianhua

According to the results of high speed photography tests, particle velocity measurement tests and the digital calculation with TP2 software, the shape of shock wave, the declined laws of the shock wave propagation speed and the peak particle velocity are described and analyzed in detail. New viewpoints about the theories of blasting fragmentation based on analysis of the progressive pictures of the fracture region are given. The formula for calculating the depth of fracture regions is established on the basis of the new viewpoints.

Jan 1, 1997

By James Stuart

A man died when the primed charge he was holding against his chest exploded. He was doing legitimate explosive work, and he was following all the safety procedures he had been taught. He and his colleagues had done this, thousands of times previously, with no ill effects.

Jan 1, 2007

By Paul Worsey, Robert Sickler

Today, America's mining and construction industries are faced with operating under a condition of reduced profit margins. This makes the implementation of new technology far more sensitive to investment return than ever before. For this reason it is imperative that every effort be made to insure that new equipment and processes be designed to maximize their impact on improved quality, reduction in production cost and enhancement of safety. Using these principles as a foundation, a study was made to evaluate potential automation techniques for the blasting industry.

Jan 1, 1987

By Jeff Yaro, Steven P. Case, Carl Kish

This project involved the construction of a new 4-story library on the campus of Cornell University in Ithaca, New York. The new building was constructed completely below grade, adjoining several of the oldest buildings on the campus. Excepting some surface soil, the job was 100% rock and the excavation had to be completed within a 3-month window.

Jan 1, 1992

By Catherine T. Aimone-Martin, Elena Oana Jacobs, Brent Meins

Accurate pressure measurements during underwater detonations are critical for the protection of structures and mitigating impacts to fish and marine mammals. Current guidelines that limit underwater pressures are based on past studies, many of which used sample rates of 48 and 65 kS/s (48,000 and 65,000 samples per second). These sample rates may be insufficient to accurately record high frequency, sharp rise time blast pressures. As such, pressure thresholds associated with fish and marine mammal injury or mortality may be underestimated, calling into question the pressure and sound pressure level guidelines that govern underwater blasting today.

Jan 1, 2019

By Denise Clarke

Homeland Security Qualifications (HSQ) personnel were instrumental in developing the UK’s suite of Explosive Substances and Articles (ESA) National Occupational Standards (NOS) (also known as "competences") on behalf of the Standards Setting Body for Explosives, Munitions and Search Occupations (SSB for EMSO).

Jan 1, 2013

Drilling through unconsolidated material I need to drill blastholes through a mix of consolidated and unconsolidated material. This material is hung up in an underground ore pass. The total length of the holes would be approximately 200 feet. We have attempted to drill through the material with conventional ITH drilling, but were unsuccessful. Does anyone have a suggestion? I am more than willing to bring in a contractor to do the job, if they have solid experience with this type of problem.

Jan 1, 2011

By Daniel Roy, Chris J. Preston, Ron J. Elliott

This paper discusses the use of pressure transducers in water filled boreholes in conjunction with surface mounted geophones to gather field data for in-situ dynamic rock properties determinations. A high speed collector is used to capture the data in the field. The calculated P and S wave velocities and rock density measurements are used as input into the Blastcalc program where the values of Young`s Modulus and Poissons Ratio are calculated. The rock properties information is used along with geological structural data and explosives properties in a 3-D blast modelling program to calculate predicted fragmentation distribution and other blast performance criteria based on the proposed blast design.

Jan 1, 1996

By Tyler Rockley, Carla Reyes

Autonomous fragmentation measurement systems designed for shovels have been in operation for nearly two decades, however fragmentation systems capable of performing in the dynamic conditions of the front-end loaders (FEL) were only recently introduced to the market. This paper presents an in-depth evaluation of an automated digital fragmentation measurement system specifically designed to perform under the dynamic operational conditions of the FEL in two of Teck’s mine sites. As early adopters of this novel application, Teck embarked on a Proof-of-Concept (PoC) trial phase, defining a set of key performance indicators (KPIs) to qualify the performance of the digital solution in tough mining operating environments. The KPIs focused primarily on the hardware robustness, quality of image and segmentation, both day and night, availability of the system and sample ratio. The benefits expected from using this technology include increasing the safety of the current fragmentation measurement process, improving the quality of the analysis, increasing the sample representativeness, and using the attributes of the system to create an oversize detection alert to inform the loading operation process. A critical part of the evaluation was verifying the system’s effectiveness on the particle segmentation algorithm as this element often gets overlooked, especially when dealing with the large number of samples autonomous systems can generate; minor misclassifications due to inadequate segmentation are often dismissed as they might not be statistically significant, however systematic misclassifications can cause unacceptable deviation in the data and limit the intended application of the technology. The system’s performance was further validated through several tests that involved identifying objects of known sizes to ensure the reliability on the consistency of the particles’ segmentation.

Jan 21, 2025