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By P Albert

A wedge-shaped underwater rock plug has to be blasted in order to tap the reservoir and furnish water to a new underground powerhouse at Manicouagan-5. The paper deals with the design and engineering aspects of drilling and blasting of this plug where the topographical configuration is extremely difficult. In this study small diameter vertical holes are considered with the OD-method and a fixed platform is recommended for drilling and loading operations.

Jan 1, 1984

By Finn Ouchterlony

"Recently detailed fragmentation data from blasts fired with electronic delay detonators (EDDs) in the Red Dog mine in Alaska were presented. They include a comparison with pyrotechnic detonators fordifferent in-­-row delays in a standard pattern and EDDs in an expanded pattern. Fragmentation was measured on the belt after the primary crusher. The Rosin-­-Rammler function (RR, two parameters) was used to describe the crusher product. This was combined with the JK SimMet crusher model and the CZM blast model (Crushed Zone Model, three to five parameters) to estimate a reasonable crusher feed (muck pile fragmentation or run of mine, ROM) for each fitted product. In this way the effect of delay timing and electronic detonators on the median fragment size x50 and uniformity coefficient n for both crusher product and the blasted rock was determined. "

Jan 1, 2012

By Rob Grant, Manuel Lopez Cano, Mike Briggs, Ken Fletcher

The scorched desert sands and life giving waters of the River Nile in Egypt have been the back drop to awe inspiring engineering feats for over 4,700 years. The latest engineering marvel to grace the land of the Pharaohs is the Mubarak Pumping Station Project at Toshka. This ambitious project aims to open up an area of 607,000 hectares (1.5 million acres) of barren desert to irrigation based farming with the supply of 29 million tonnes (32 million tons) of water per day, drawn from Lake Nasser on the river Nile. It is anticipated that this currently unpopulated area of southern Egypt will soon flourish and become home to several million Egyptians who will conduct their lives around the water supplied by the 230 kilometers (144 miles) of concrete canals. An integral part of the pumping station is the intake canal. The canal was excavated in two sections – the dry excavation, and the wet excavation. The wet excavation comprised of some 5.5 million cubic meters (7.2 million cubic yards) of rock to be drilled, blasted, and excavated, from the surface of the lake. The challenge at hand was how to achieve this safely, quickly, and cost effectively, with water depths of up to 45 meters (148 feet), excavation depths of up to 47 meters (154 feet), blast production rate peaks of up to 30,000 bank cubic meters (39,200 bank cubic yards) per day, blistering summer air temperatures up to 60°C (140°F), and security concerns about the storage of large quantities of explosives in the Middle East region. The solutions to these challenges were engineered by UEE Explosives and centered around the use of a microgel bulk explosive called Rioflex™ and an international team of engineers and operators from three continents. The microgel and accompanying pumping system allowed pumping rates of up to 17,400 kg (38,400 lb) per day, and more importantly, enabled the bulk product to remain as an oxidizing matrix whilst in transport and storage, transforming into an explosive only moments before being pumped into the blastholes. This case study outlines the underwater drill and blast process employed at the Mubarak Pumping Station Project at Toshka, and the novel solutions to the unique challenges encountered.

Jan 1, 2004

By D. Mason, W. J. Birch

Blasting operations are arguably one of the most contentious areas of surface mining.Many operators carry out outine monitoring as required by Mineral Planning Authorities. However in so doing they only concentrate on the observed Maximum Peak Particle Velocity (PPV) being below the statutory limit and pay little or no attention to the measurable parameters that determine this value (e.g. scaled distance, burden, detonator type, blast type or rock type). Such practice is “monitoring to comply”. What is needed is for the operators to adopt a methodology that clearly demonstrates to the appropriate regulators that the operator is “planning to comply”. The aim of the exercise being to deliver a process that is seen to be transparent, accountable, and quantifiable, which seeks to minimise environmental impact whilst not compromising the efficiency of the blasting operations mine.

Jan 1, 2011

By Richard J. Mainiero

Traditional techniques for the experimental determination of toxic fumes produced by the detonation of high explosives are not applicable to blasting agents. To detonate properly, blasting agents require confinement, a significant booster, charge diameters of 3 inches (7.5 cm) or greater, and charge lengths greater than two times the charge diameter. Without these conditions, blasting agents will not detonate at full order, leading to a misrepresentation of the gaseous products.

Jan 1, 1997

By Tom Short

The contract to drive twin 4,100 foot (1250.5m) long tunnels under the existing Cumberland Gap highway was awarded to a Joint Venture of S.A. Healy of Chicago, Illinois and Lodigiani USA of Fairfax, Virginia in January of 1991 under a $51.8 million bid. Due to very complex geological conditions, there were six distinct categories of excavation, the New Austrian Method of ground support was utilized throughout.

Jan 1, 1993

By M Sampara, W Comeau

The introduction of large-diameter holes to underground mining has made possible the development of new mining methods such as the Vertical Crater Retreat (V.C.R.) method. It is not only the safest underground excavation system but also provides mass production at a lower cost than any conventional mining method (1, 2, 3, 4, 5).

Jan 1, 1981

By C. Partouche, T. Bernard

Blasting engineers are mainly concerned about fragmentation issues. Even further, this is the final goal of using explosives. A lot of models have been developed for controlling fragmentation distribution, but most of the time, they are based on physical phenomena using field data as input for rock characteristics. Fragmentation is a result of two phenomena: waves from the borehole, damaging and cracking the rock, and gas pressure, widening those cracks and spreading out rock fragments. This model simulates the P wave escaping from boreholes and the cracks created by these P waves. It takes into account rock characteristics, provided by digital imaging, and explosive characteristics coming from VOD measurements. What we need to focus on, is the interaction of P waves coming from each borehole related to different timing sequences. This paper presents several simulations that show the influence of the timing and the sequence accuracy on the fragmentation distribution.

Jan 1, 2002

By Gerald R. Coonan

Early in the open session of the 1979 SEE Fifth Conference panel discussion, someone asked a question of the panel concerning the future intent of the Office of Surface Mining and the regulatory limits established for ground vibration and air blast. The "gist" of the question was: "What assurances do we have that OSM will not promulgate a limit of 0.5 inch per second ground vibration, or some other number within the next two years or so."

Jan 1, 1979

By Jose A. Sanchidrián, Ricardo Castedo, Pablo Segarra, Juan Navarro

A study conducted at a mine site that used traditional field surveying and physical hole spot markings bench marked their combined drill and blast performance. The analysis of the operational expenditure (OPEX) improvement determined there were many measurable cost improvements. A primary factor that most operations have to deal with is over drilling of holes. This alone impacts the cost due to nonproductive labor allocations, excessive explosive costs, increased drill tool costs, increased drilling costs and has an impact on the downstream operation cost such as digging the shot material. Other related investigations also show a downstream impact of poor fragmentation on digging payload tonnes, cycle times, haulage payload tonnes, time to load a truck and the number of passes to load the tuck. The intent of this presentation is to draw attention to aspects of mining we understand but may be missing the big picture effects, such as the ability to reduce the operational expenditures consistently to impact the bottom line. The target audience is across the board from owner operators, drill and blast contractors to blasting contractors. Everyone can benefit from these improvements.

Jan 1, 2019

By Jerome H. Stofleth

In June of 1998, the DeBruce Grain Elevator was devastated by an accidental explosion caused by the unintentional ignition of grain dust. The DeBruce grain elevator was the largest ‘single head-house’ grain elevator in the nation. It was comprised of 450 cylindrical grain silos, 30 feet in diameter by 120 feet tall, with a centrally located headhouse. Immediately after the explosion, rescue operations were started for seven missing workers. The Federal Emergency Management Agency (FEMA) had taken over operations of the site by day two. On day three FEMA contacted the Washington DC office of the Department of Energy for explosive expertise, who in turn contacted explosives experts at Sandia National Laboratories (SNL) and Los Alamos National Laboratories (LANL). FEMA was looking for guidance in making the decision to downgrade their operation from a rescue to a recovery operation. Based on some chemical equilibrium calculations, and basic explosive engineering techniques, the SNL/LANL team was able to provide the necessary input to allow the decision to be made for the operational downgrade. At this point, only one worker remained un-recovered.

Jan 1, 2004

By Robert Hopler

GEO. M. MOWBRAY’S REFRIGERATOR CAR FOR THE SAFE CONVEYANCE OF EXPLOSIVES. It is a fact well known to all miners who have used nitro-glycerin, or any of its adulterations, commonly known as dynamite, rendrock, Hercules’ powder, dualin, vigorite, etc., that when congealed, these compounds cannot be exploded, and in this congealed state — say at temperatures below 40° F. — they can be handled with no more danger than a box of soap or a can of lard. If, then, the atmosphere by which this class of explosives is surrounded, during transportation, be maintained below 40° F., explosion is practically annihilated. Therefore, I constructed a refrigerator car, with cells for every box of the explosive; and two years of railroad transportation confirms our ten years’ experience in teaming in wagons, that this class of explosives can be transported in perfect safety, as above described.

Jan 1, 2011

By Jaak J. K Daemen, Clayton R. Morlock

A study was performed to evaluate the predictability of airblast overpressures induces by production mine blasting. Thirty-seven production blasts were monitored using 3 blasting seismographs giving over 100 blast overpressure records. Blasts were monitored at 5 coal highwall operations and at a limestone quarry, all in the midwest. Blasts consisting of small surface charges were monitored to permit an assessment of prediction methods under controlled conditions, as well as to observe actual delay intervals and their influence on the overpressure.

Jan 1, 1983

By John Kemeny

There are many methods used to predict blast fragmentation, including empirical and numerical models, field trials, and experience from ongoing blasting. All of these methods require an accurate measurement or prediction of the rock mass properties. These properties include the characteristics of the rock fractures, including fracture density, friction angle, orientation, length, roughness, fill, etc. They also include the hardness of the intact rock, water content, and other parameters. This paper describes three new technologies that can be used to automatically or semi-automatically obtain rock mass properties: digital image processing, 3D laserscanners, and drill monitoring systems. Each of these technologies is described, including the current state of the art, current limitations, and their future potential. Each of these three technologies has advantages and disadvantages. These new technologies, however, have the potential for providing accurate rock mass information in an automated and real time fashion. This information can then form the basis for a new generation of real-time, database driven blast fragmentation models.

Jan 1, 2004

By Ed O'Connor, Per-Anders Persson, Manhong Zhou

This chapter deals with the concepts of shock waves and detonation waves together, because a detonation wave is really a shock wave, supported by the explosive reaction that the shock wave ignites and propagates as it travels through the explosive material. In the context of rock blasting, furthermore, there is justification for treating shock waves and detonation waves together, because the mechanical effect of the detonation in an explosive in a drillhole in rock is propagated and its effects are spread throughout the surrounding rock by means of a shock wave. The overall performance of an explosive in rock blasting or any other application is of course dependent on how much thermal energy is released in the chemical reaction that occurs when the material detonates, and on how much useful mechanical work the reaction products can do as they expand. A major portion of this chapter deals with the prediction and measurement of explosive performance, a subject which is now still in a process of rapid development.

Jan 1, 1997

By Shao Li, Chen Zhiming, Wu Jihong

In this paper,powder emulsion explosives,which have high sensitivity and strong detonation force,have been studied by applying emulsion technology to the production of the present powder ones.Under the condition of #8 industrial detonator initiation,the distance of air gap propagation is 110~180mm,brisance !3.5mm, lead block test value 325ml and detonation velocity 3000~4000m/s for small diameter (35mm) explosive cartridges.In addition to these,the factors effect on are investigated by experimental study and theoretical analysis.

Jan 1, 1991

By Virgil J. Stachura, Larry R. Fletcher, Paul V. Sterk, Matthew N. Plis

The large diameter blastholes now being used in underground mining have caused concern because of their increased potential for damaging openings and creating rockfall hazards. In response to this situation, the Bureau of Mines is conducting research to reduce the amount of overbreak and damage to the perimeter of underground openings. This paper presents the results of tests with decoupled charges in 6.5 inch diameter blastholes, and unloaded guide holes, in Vertical Crater Retreat (VCR) stope panels at the Homestake underground gold mine in Lead, SD.

Jan 1, 1991

By Ulrich Leiste

If the iron ore loss is 15% in the process of mining, the total iron ore loss in the world will be about 461 million tons, this is equal to the total production of 230 iron ore mines each of which produces 2 million-tons of iron ore per year. Based on a series of blast tests in the Malmberget mine, this paper shows that ore recovery can be markedly increased by improving blasting technology such as choosing a correct primer position and making use of shock wave collision. The paper further suggests that a high ore recovery can not only reduce natural resource loss and mining cost but also prolong the life of a mine. In addition, the paper shows an example of reducing blast-caused rock damage in the roofs and walls of underground drifts (tunnels) by using new blasting methods in the Malmberget mine. Finally, the paper shows how the Malmberget mine has successfully reduced the ground vibrations, without adversely affecting fragmentation and ore recovery in sublevel caving mining.

Jan 1, 2014

By Michael Wieland

Work-principle computations for explosions underwater or in rock reveal the way the thermodynamic characteristics of surrounding material influence the resulting shock and heave. To reach total thermodynamic equilibrium under such transitory dynamic circumstances, reactions must quickly readjust to changing circumstances, which works for molecular (military) explosives where the fuel and oxidizer type atoms are originally in close proximity. For non-molecular mixtures with their dispersed zones of oxidizer or fuel, in particle or droplet form, there are numerous unproductive collisions, increasing the wait time required to reach chemical equilibrium. Underwater test data for molecular explosives compare rather well with the shock and heave resolved from the work-principal model, while the non-molecular explosives normally used in mining tend to yield a noticeable discrepancy. Years ago, it was recognized that the underwater shock was lower than expected and the heave was higher than expected for ammonium nitrate fuel oil (ANFO), though their resultant sum for the total work was roughly what was expected. When the readjustment of thermodynamic equilibrium warrants quicker chemistry than occurs in underwater or rock shooting, the time-retarded chemistry reduces the shock and raises the heave within the surrounding material without reducing the total work, unless the reaction retardation is quite severe. This technical complication in reality is a nonequilibrium issue that is difficult to resolve with just thermodynamics, though a rational set of transformation factors is formulated herein to represent those circumstances.

Jan 1, 2008

By Joseph W. Hejny, Marlyn G. King

Coal mining in the Powder River Basin has changed in recent years to accommodate the large quantity of coal produced. With strip ratios of one to one and up to three to one, extensive amounts of overburden have to be removed to get to the large thick seams of coal. Larger shovels and trucks have been implemented in the removal of this overburden. The addition of draglines and continuous miners have been added to increase the production of coal. Drills used today are capable of drilling up to 13.5 inch blast holes.

Jan 1, 1994