Search Documents

By Mick Fritz, Ryan Gilmore

The Center for Disease Control [CDC] is in the midst of a twenty year project, part of which includes demolishing existing buildings and erecting taller, more modern structures within the same foundation foot print. Controlled Blasting Inc, a large and experienced construction drilling and blasting company in Metro Atlanta, was contracted to provide the drilling and blasting for the new building foundations. Working on a construction site, in this type of environment, creates many challenges for the drilling and blasting crews.

Jan 1, 2008

By Robert Hopler

RBH Note: in 1913 black powder was still dominant as a coal-mining explosive, but permissible explosives were making some slight headway. For example, in 1902 there were only 11,300 pounds of permissibles used in coal mining, but in 1913 the quantity was 21,801,285 pounds. However, there were 187,551,653 pounds of black powder used that year. It took many years before the use of black powder ended in coal mining. From the picture of the miner reparing his explosives it’s hard to tell what he’s using, but the fact that a wooden Du Pont powder box is shown, he’s probably not using black powder. That doesn’t mean he’s using a permissible, either, since that was not yet a requirement. It’s interesting that the miners have open flame cap lamps, and the miner is actually smoking a pipe while preparing his explosives.

Jan 1, 2014

A major problem that has continued to plague the surface coal industry is blast induced damage to the coal seam. Atlas Powder Company has addresssed this situation through seven years of field research in full-scale production environments. Many operations across the United States have been evaluated.

Jan 1, 1990

By Goran Lande, Bernt Larsson, Dennis Clark

The effects of vibrations on close surroundings has been studied in Europe and the United States extensively in the past three to four years due to the ever increasing demands of environmental control. Therefore, "routine measurements" or "standard vibration consulting services" are being carried out by numerous firms with widely different qualifications.

Jan 1, 1983

By Allen Kinney, P. T. Freeport

This paper presents the methodology for final wall-controlled blasting utilized at the Grasberg Mine. The resulting optimized slopes representa14%and17% increase to bench face angle (BFA) and inter-ramp slope angle (ISA), respectively. The corresponding increase in both copper and gold recovery was more than 40% greater than forecast for each material. The Grasberg open pit mine is located in the remote jungle province of West Papua Indonesia, at an elevation of 4,200 meters(13,780 ft).With a diameter of approximately 3.5km(2.2 mi), anddepthover1.2km(0.7 mi),P.T. Freeport Indonesia (PTFI)has mined billions of tons of rock from one of the world’s largest gold and copper deposits. Grasberg Operation and Engineering implemented a quality driven slope optimization program for the final pushback, with the goal to safely increase recoverable metal through steeper slopes, while utilizing existing infrastructure and equipment. This paper focuses on controlled blasting initiatives, blast monitoring, and as-built slope measurement tracking, although many groups contributed to the success of Grasberg slope optimization. The potential slope optimization area was divided into two sections based on geologic assessment: Area A at radial 200°-270° and Area B at radial 270°-360°. Original slope designs for areas A and B specified ISAs of 51° and 52°, respectively, with all BFAs in the pit at 70°. Through continuous development, collaboration and achievement, the Grasberg final pit accomplished a BFA increase to 80°for all areas, and an ISA increase from 51° to 56°in Area A, and 52°to 60° in Area B.

By Jorge Flores, Dean Nichols

Some view quantitative risk assessment (QRA) as difficult to understand and complicated to use. They are comfortable with the proven reliability of quantity distance (QD) and question the benefits of applying QRA principles to explosive safety. In response to such questions, a review of the history of the American Table of Distances (ATD) provides insight to the strengths and weaknesses of the concepts behind QD tables. Additionally, a closer look at QRA features that are available today will reveal stunning capabilities and improved user friendliness not available previously. This paper looks at the early days of explosive safety, the use and limitations of QD, the meaning of risk in the context of QRA and discusses recent developments that knock down barriers previously hindering acceptance of QRA among regulatory agencies.

Jan 1, 2015

By Francisco Sena Leite, Vincius Miranda, PhD Machado Leite, PhD Pinto, Raquel Carvalhinha, Alexandre Julio, Dorival de Carvalho

Rock blasting, in particularly the drilling process, is one of the first processes in the stage of rock fragmentation and plays a fundamental role by influencing all the following stages. Given its importance, some proposals to optimize this process have been presented over the last few years. These proposals, while having different approaches, aim (in a large part) to minimize the costs of drilling and blasting respecting the limits of fragmentation required by primary crushing. Reviewing some recent articles leads us to an enriching experience, since the authors of these articles clearly model the problem, but do not address the mathematical solution of these models, which in turn, given their non-linear nature, have no directly and easy solution. Simple and even robust optimizers present in the market show different results and often do not converge to a single solution. To address this problem, an adapted gradient heuristicbased model was developed to try to find optimum values. Heuristics search for values of stemming, subdrilling, burden and spacing that minimize the costs of blasting and drilling. This search, which by the nature of the heuristic moves the solution in the direction of the gradient with maximum decrease to find optimal solution, found values that in turn, when compared with values presented by market solutions not only equaled them as, in some situations, even improved the proposed solution. The algorithm was tested and validated on the field, and although the results have already been presented in papers published in the last year by the authors of this paper, it is now presented with its mathematical formulation and comparison with the other solutions. This approach is expected to be able to improve (and even demystify) the process of pattern expansion and be the basis for future work in the continuation of the optimization process.

Jan 1, 2019

By Samir Garcia, Alain Mestanza

This technical work was carried out in an open pit copper mining unit, located in central Peru, which has a daily production of 440 thousand tons per day. Currently the pit consists of three mining phases, however, in phase 05 north, there is the construction of a shaft with a height of 375 meters, the function of this structure is to collect and drain the water coming from the pit, there is the importance of preserving its stability and keeping it operational, guaranteeing the sustainability of the operation. For this, a controlled blasting plan was developed that goes from level 4530 to level 4455 to place the central well on a bench, reactivating the pools.

Jan 21, 2025

By R. F. Favreau, Favreau Patrice

"The economy profits from the rock excavated in mines and quarries and the excavations required for the construction of roads and buildings. However such excavations are achieved by blasting withexplosives, and explosions create fly rock and vibrations which in some cases may throw rock far intoinhabited regions and may vibrate buildings excessively in these regions. Society, however, no longeraccepts that their quality of life be disturbed by the risks of fly rock or the perturbation of vibrations.Thus it is important to know how to design blasts that do not cause excessive fly rock or vibrations, and to understand why sometimes a blast does create excessive vibration or fly rock. An article presented at the 2015 ISEE (reference 1) explains how unacceptable vibrations can be avoided, while the present article explains why dangerous fly rock occurs and how it can be avoided. The article shows by rigorous calculations with the blast simulator Blaspa that long range fly rock can be due to short collar or short burden, but mainly it explains how inadequate blasting that allows the floor to rise can cause even further reaching fly rock, a situation not usually recognized by most blasters."

Jan 1, 2016

By David Harrison

The Charleroi Locks and Dam (Figure 1) was completed in 1932 and is located on the Monongahela River, approximately 22 miles (35 km) south of Pittsburgh, in Charleroi, Pennsylvania. It is comprised of a 420 foot (128 m) gated dam, and a 720 foot (219 m) by 56 foot (17 m) land side lock which provides for a 16.6 foot (5 m) vertical lift.

Jan 1, 2015

By David E. Siskind

In the early 1980's, the Bureau of Mines published four reports of structural response and damage from surface mine blasting, vibration monitoring, and analysis methods. These findings replaced simpler and less restrictive Bureau criteria dating back to 1962 for ground vibration and 1943 for airblast.

Jan 1, 1991

By Thierry Bernard, Philippe Dozohne

May 13th, in the back country of Nice @arice) collapsed a complete piece of mountain, cutting the RN 2085 and destroying a part of Valabfre’s viaduct. The fist inspections of the site showed that materials had broken loose from surrounding cliffs, The geologists discovered that a block of several thousands of m3 remained suspended in cliff and that it presented a risk raised of gliding. Decision to destroy it by blasting in one blast was there taken by the French department’s council of the Maritime Alps. A race against the clock engaged. Indeed, the RN on 2085 is the main axis connecting the village of Saint Etienne de Tinee and the resort station of ISOLA in the centre of Nice

Jan 1, 2001

By John L. Didlinger

We all hate the paper work in keeping accurate blasting records. Nevertheless, have you ever thought what those records could show you? Think about it. Those records could show you vibrations, noise, and safety problems. They could show you the ratio of powder used and tons produced, the cost per foot, even help negotiations for pricing.

Jan 1, 1997

By Duane Skidmore, Francis Otuonye, Calvin J. Konya

Proper stemming not only affects the rock breakage process, but also controls the unwanted side effects of blasting such as airblast, ground vibration, and flyrock. Little research has been conducted on the behavior of borehole stemming material under high pressure loading conditions. The methods of selecting stemming particle size and necessary stemming length were previously determined only by trial and error in the field.

Jan 1, 1982

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 Yong Pan, Purushotham Tukkaraja

It has been well understood that blasting is the cost-effective method for breaking rocks as compared with the mechanical systems. However, vibrations induced by blasting in open-pit mines could pose problems to the structures surrounding the mine site. Blast-induced ground vibration has been the subject of research for several studies in the past; because of the complex nature of blasting mechanism, it is difficult to predict blast-induced vibrations. Even though there are several approaches proposed by the previous researchers, traditional regression analysis is still playing an important role in predicting blast-inducedgroundvibrations.

Jan 1, 2019

By Greg S. Williams, David L. McDorman, Richard W. Givens

This paper examines the effect of prill size consistency, internal particle density, and oil absorbency on Ammonium Nitrate Fuel Oil (ANFO)-emulsion blends. By analyzing these physical properties of prill and the nature of the blending process, a mathematical model has been developed to theoretically predict blend densities. Calculated densities can now be compared to actual field densities to give an operator a basis for comparing various manufacturers' emulsions and Ammonium Nitrate (AN) during bid solicitation. The lowest priced emulsion and/or AN may not be the most economical, due to the impact of specific physical characteristics. These factors dictate the blending mechanics and resulting density yields for various mixes. The research was driven from observed 'field' mixing relationships and data. Ultimately, such a model can be an effective tool in evaluating blends from a cost and performance basis.

Jan 1, 1990

By Stuart Brashear, Robert Brush, Ben Cook

In early 1993, the Piney River quarry owned and operated by the Blue Ridge Stone Corporation of W.W. Boxley, received a series of complaints from the owners of a 130 year-old historic farmhouse that had been converted into a bed and breakfast establishment. Since the distance from the quarry to the farmhouse was substantial, a unique method of seismic data acquisition was utilized to determine if perceived blast effects were caused by air blast or low amplitude, low frequency ground vibration.

Jan 1, 1995

By Josh Calnan, Paul M. Holmgren, Abigail N. Styer

Detonating cord is a staple of the explosives industry, used widely in the civil and defense industries. Detonating cord is a thin, flexible plastic tube filled with pentaerythritol tetranitrate (PETN). It has many applications in mining, construction and military disciplines. For civil applications, it is used to connect and initiate a series of blastholes in a desired pattern. In the defense sector, it can be used as a detonating agent, a priming agent or alone as an explosive charge. Research has been done to understand the initiation and detonation physics on the detonating cord. However, its sympathetic detonation characteristics needed to be further analyzed.

Feb 1, 2020

By Thomas Barkley

Until the recent past, blasters have provided good to excellent results with tools and processes that have an inherent error. These errors can be found in drilling, explosives delivery quality and consistency, explosives loading consistency, actual explosives performance, and pyrotechnic detonator initiator accuracy. My experience and data from several decades in the industry show the error is often times 10% or higher larger in the dimensions that measure the performance of each of these tools and processes.

Jan 1, 2011