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By Sérgio Augusto Ferreira, Alan Gerson Diaz Butron, Carlos E. Arroyo, Marcus Neves, Jorhs Enrique Casimiro Huayhua, Dieggo Santos, Eventomar Junior

The presence of natural underground cavities is normally a characteristic of iron ore deposits, specifically in tropical deposits. Brazil and the United States are the only countries that have a legislation to protect these structures, but in Brazil this legislation is very specific for the existing cavities in the federal territory. These cavities are classified by their level of relevance as high, medium, and low. From this perspective, its preservation becomes mandatory, especially, for those of high relevance in order to protect the species (flora and fauna) that live in them. When these structures are within the production phases, it becomes a challenge to exploit these reserves with the use of commercial explosives, since these structures condition and may restrict the use and amount of explosive charge. This paper presents the methodology of controlled blasting associated with predictability via realistic simulation in production polygons, applied in a Brazilian iron ore mine where there is a presence of high relevance natural cavities with restrictions in relation to the limits of Peak Particle Velocity (PPV), which is product of detonation.

Feb 6, 2023

By E. Lentilucci, A. Dey, X. Liu, A. Datta, S. Ghosh

The segmentation of quarry blast smoke plumes is a crucial research area that has the potential to enhance safety, environmental monitoring, object detection, and regulatory compliance in the mining industry. Smoke plume segmentation can be used to identify the spatial extent and temporal evolution of smoke plumes generated by the blast. This information can be used to improve the understanding of blast dynamics and optimize blast designs. Furthermore, smoke plume segmentation can assist in identifying potential environmental and health hazards associated with the release of smoke and dust particles into the atmosphere during quarry blasts. However, many current smoke plume segmentation algorithms are designed for segmentation of smoke plumes from fires and are not suitable for segmentation of plumes from quarry blasts. The proposed method in this paper leverages the video frame captured before the blast as a stationary background image, which helps to reduce other confuser objects present in the image along with a selfadaptive clustering method. The color channels of the image are utilized based on the different contrast properties of the smoke, with a self-adaptive gradient compensation applied for edge detection of the smoke plume. This approach offers a novel and effective way to segment smoke in quarry blast analysis, with potential applications in the calculation of noxious gas volume and concentration within the plume. Compared to other algorithms, our method improves accuracy, decreases the false alarm rates, and reduces the overall miss rate. Overall, this paper contributes to the research on smoke plume image segmentation, particularly for quarry blast smoke plumes, which possess unique characteristics that require specialized algorithms for accurate segmentation.

Jan 1, 2024

By Gerard McAlinden, Daniel Frost, Patrick McAlinden, James McAlinden

In an effort to recover Polychlorinated biphenyls (PCB’s) that had leached into bedrock below the Hudson River in Upstate New York, a shaft and tunnel complex was designed that would allow installation of inclined and vertical wells into the zones of contamination to recover PCB’s by gravity. A joint venture of Merco Inc., of Lebanon, NJ, and Obayashi Corporation, of San Francisco, CA, was awarded the contract for constructing the first Tunnel Drain Collection System in the world. Conventional drill and blast techniques were the most economical method to construct the project but due to the presence of PCB’s and community concerns, innovative drill and blast practices were needed.

Jan 1, 2010

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 Corry Goumans, Ron J. Elliot

This paper discusses the challenges encountered in drilling and blasting of a small diameter shaft underneath a parking garage in historic Gastown, Vancouver, BC. This project involved drilling in a restricted headroom area, blasting in a confined space environment, and excavating using a novel vacuum technique. The 1.2m x 1.2 m x 8.5m deep shaft was required for installation of a hydraulic piston for a show lift. The project called for very accurate drilling through inter-bedded sandstone and siltstone within the water table. Development of a unique blast design was required for blast vibration control on a historic structure located just 15.8 meters away. The shaft was successfully completed without damage to any of the surrounding structures.

Jan 1, 2004

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

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 Shuli Teng, Vladimir Sujansky, Matthew Rawls, Ivan Junarsa

In recent years significant advances have been made in chemical processing technology. In particular, process intensification using micro-technology has had some success in changing and improving chemical processes including mixing. Process Intensification is the miniaturization of unit operations and processes whereby a smaller compact piece of equipment takes the place of a larger one at the same given capacity or mass flow rate. This paper summarizes research into the application of the technology for manufacture of high internal phase water in oil ammonium nitrate emulsions (ANE’s) at low energy cost and with very low oil/fuel blend content. The emulsions can be used as precursors for preparation of explosives. The quality of the emulsion prepared was assessed through droplet and crystal analysis and compared with that of emulsions made by conventional large scale jet mixing technology.

Jan 1, 2014

By S. S. Bud Jenkins

I went to an underground limestone mine recently to demonstrate the use of borehole liners. The liners were for horizontal holes in a normal “V” cut tunnel round. I hadn’t been in this mine for about 40 years. What a change. Way back they used cap and fuse and lit each fuse individually with a blowtorch. The face was about 40 feet wide and 14 to 16 feet high. They used ladders to get to the upper holes. The rounds were mostly slab rounds. I never saw this happen but had heard several times that the first holes were going off before the last holes were lit. I guess if this was true the use of slab rounds was a plus for safety. As far as I know they never had an accident but it was a scary procedure. There were a lot of scary procedures in the past and thankfully things have changed.

Jan 1, 2010

By David G. Paton

"Electromagnetic surveys were conducted at the BXL Bulk Explosives Limited Mixing Plant andsurrounding area to characterize runoff from the site and possible impacts of salinity. The BXL Plant is located at the edge of a depressional area and any escape of soluble ions, such as nitrates, would have ended up in the slough to the west of the plant. Two electromagnetic (EM) instruments were used in the survey. A Geonics EM 3 1 was used in October 1997 and in June 1998, a new multifrequency instrument, a GSSI GEM 300 was also tested. Both instruments were individually mounted on a plastic sled with Teflon runners and towed with an ATV quad. Position was determined using a Trimble Pro XL global positioning system (GPS) with a real time correction mode Landstar receiver for an accuracy of about *l m. Both GPS and EM instruments were set to collect data at 1 second intervals. The quadrature maps for both instruments showed essentially the same information, namely of very high conductivity, appearing to emanate from the mixing plant. The levels of conductivity were highest where the saline water appeared to pool, at the southern end of the slough. Soil sampling locations were identified from the EM maps and navigated to using the real time GPS. Composite samples were collected by hand using a Dutch auger, from two locations, in increments of O-1 5, 15-30, 30-60 and 60- 90 cm. The analysis of the soil samples indicated a complete absence of nitrate or ammonium ions; the major anion was sulphate, indicating naturally saline subsoil conditions. The GEM 300 made the collection of data more efficient, as only one pass was required to collect the data from four depth intervals. The EM survey combined with the real time GPS allowed rapid characterization of the site with respect to soil salinity and proved to be cost-effective for Phase l/ Phase 2 site assessments and targeting sampling locations."

Jan 1, 1999

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 Bruce R. Leland, Steven H. Smith, John D. Paulson

The USDA - Wildlife Services has been removing beaver dams with explosives for over 30 years. This paper will discuss the history of the explosives program, summarize how we've evolved, and highlight our work removing beaver dams in unique locations.

Feb 1, 2020

By Steven D. Knudsen, Dale S. Preece

The spherical element computer code DMC (Distinct Motion Code) used to model rock motion resulting from blasting has been enhanced to allow routine computer simulations of bench blasting. The enhancements required for bench blast simulation include: 1) modifying the gas flow portion of DMC, 2) adding a new explosive gas equation of state capability, 3) modifying the porosity calculation, and 4) accounting for blastwell spacing parallel to the face.

Jan 1, 1992

By Brent Blanchard

As most veterans of our industry are aware, explosive demolition by its very nature is often a challenging proposition. Even under the best of circumstances, proper planning and care must be taken during a variety of processes to ensure a safe, successful result. However, every now and then a project suddenly arises where safety, timing and cost factors combine to form a critical scenario requiring rapid execution in an environment far more challenging than the norm. On these occasions, the stresses, complications - and most notably the dangers - related to the industry increase exponentially, and conspire to test the mettle of even the most seasoned experts.

Jan 1, 2003

By Roy McKinstry

In March of 2001, Barrick Goldstrike became the first surface gold operation in North America to evaluate the advantages of electronic detonators. A detailed study was conducted to quantify the benefits of the use of electronic detonators to the downstream excavation, crushing and ore processing operations. The following methods were used to quantify blast performance: High speed film and video monitoring Firing time and rock response analysis of the high-speed films Digital fragmentation analysis of the post blast muckpile Vibration waveform analysis (including Fast Fourier Transforms and seed waveform modeling) Excavator performance quantification Crusher, SAG mill and ball mill performance evaluation Ore recovery analysis Cost/benefit analysis

Jan 1, 2002

By Thad M. Jones

This paper considers the sampling, digitizing and reconstruction of seismic signals. A sampling frequency range is proposed and a minimum limit is suggested. Digitizing precision criteria for both peak velocity and analysis applications are given. Several methods for reconstructing signals from sampled data are presented.

Jan 1, 1985

By Francis Otuonye

Rock fragmentation by blasting still remains the most common and cost-effective method of excavating hard rock in mining and tunneling operations. During blasting, the dynamic stresses induced by the detonation of the explosive, in addition to fragmenting the rock in the vicinity of the blast, may fracture the rock at considerable distances from the point of detonation of the explosive. The fractures can result in reduced mine safety, increased costs to support the opening, low productivity and perhaps high ore dilution. Besides the dynamic stresses produced in the rock, air blast overpressure pulses are generated and propagate through the network of underground mine openings. The waves, unable to spread out spherically or hemispherically like blast waves from surface blasting, are forced to propagate by reflection from the roof, ribs and floor down the drift. Blast wave focusing can occur and produce intense shock waves that could damage ventilation barriers such as cement block stoppings.

Jan 1, 1992

Hello, everyone. Way back in 1965, Devine and others at the US Bureau of Mines showed that a presplit fracture plane did not affect vibration levels transmitted across the plane (RI 6695).

Jan 1, 2010

By Dr. Paul Worsey, Dr. Calvin Konya, Dr. Anthony Konya

Development of methods to calculate presplit blasthole pressures through simplified models, namely the Empirical Model and the Detonation Pressure Model. These models can be used with variations in explosive type and diameter, along with borehole diameter. All models have been validated with test data and shown to have minimal error.

Feb 1, 2020

By D E. Shaw, J B. Case, J Gusek

Explosive casting of overburden is defined as the use of explosives in blasting to move overburden to a spoil pile without rehandling. Studies of the economic feasibility of the method, and the formulation of a design hypothesis involving rock properties, and blasthole geometry are presented. These studies indicate that if technical feasibility can be demonstrated to increase surface coal production, considerable economic advantage would accrue to coal mine operators.

Jan 1, 1980