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By Satish R. Kate

Explosive is a chemical energy, which on detonation is released instantaneously with extremely high speed and under high pressure. It is used to meet the basic requirement for breaking of rocks. The productivity is the function of Drilling, Explosives and Fragmentation. Thus, the quality of explosives (energy content) is the key to get desired fragmentation. The variation in energy of explosives and volume of rock per hole have direct impact on fragmentation and cost of excavation (drilling and explosive costs). With the application of higher and higher energy content explosives, it is possible to expand the drilling patterns, i.e. volume in cum. per borehole. As such, higher drill productivity and higher production from the given number of holes can be achieved by adopting appropriate energy content in explosives, and suitable drill pattern for getting desired fragmentation.

Jan 1, 1998

By B Mohanty

The current basis for rating of commercial explosives is examined, with particular emphasis on calculated bulk and weight strengths, detonation velocity and underwater energy measurement. The calculated strengths still form the basis for selecting explosives for most blasting applications, with the measured detonation parameters serving only as a measure of the quality of the explosive. The major drawbacks with this approach are discussed, in view of the non-ideal nature of commercial explosives and the field conditions prevalent during the blasting operation. A unified approach to rating explosives on the basis of blasting performance rather than calculated energy alone is presented for various types of explosives. This incorporates the relevant field parameters as well as the effect of non-ideal reactions, both of which affect explosive energy release and its transfer to target rock.

Jan 1, 1988

By G. R. Adhikari

A major part of mineral production comes from surface mining and there has been a rapid growth in this sector with the deployment of high capacity equipment. The importance of blast design combining appropriately both theoretical methods and practical approach has been well recognized in the field of surface mining. It is known that blast design has a direct consequence on productivity, safety and economic viability of these mines. Blasting is the most common method of breaking rocks in mining, but it has to be cost-effective. In coal production, for instance, drilling and blasting account for 25 percent of the total procution cost. In hard rock mining, the cost of drilling and blasting is about 40 percent. Due to ever increasing concern for cost-effectiveness together with environmental consciousness, designing blasts for each application has now become a stringent requirement and indeed a challenging task as well.

Jan 1, 2002

By Robert Hopler

Torpedoing Wells. – On the completion of the drilling, or when the production is found to decrease, it is usual to “torpedo” the well to increase the flow. This process was patented in 1862 by Colonel Roberts, who believed, with many others, that the oil was contained in crevices in the rock, which might not have been tapped by the bore-hole. He therefore proposed the use of nitroglycerine, gunpowder, or other explosive, to break up the rock at the bottom of the well, so that these rich “pockets” might be brought into communication with the well.

Jan 1, 2007

By Craig Wilbour, John Stimberis, Rob Gibson, Lee Redden

Active avalanche control is the intentional triggering of avalanches while people are kept out of the hazard area. Explosives are frequently the most effective tool for triggering avalances. In a highway setting an avalanche control program will reduce total highway closure time, while providing greater safety to motorists and maintenance personnel. Avalanche control with explosives is effective when the snow is somewhat unstable and almost ready to slide naturally. Forecasting this condition involves having a network of local meteorological stations, examining snow structure, using mountain weather forecasts, doing snow strength tests, and having the results of ski and explosive tests. The method of delivery of explosives to an avalanche starting zone is governed by the accessibility of the starting zone. Common methods include; hand placing or throwing charges, remote delivery cableways, or "trams", surplus military weapons, and a compressed gas charge launcher, or "Avalauncher". Charges dropped from helicopters are also occasionally use. We have increased the effectiveness of our program by use of large elevated charges. Efforts are being made around the world to develop and utilize better methods for the safe, remote initiation, but procedures have varied dramatically between individual control programs. There is now a movement to review and standardize operational guidelines for avalanche control. Highway avalanche control is often done at night, during winter mountain storms. Heavy rain or snow, high winds, and high avalanche hazard, are common work site conditions. Commercial and economic pressures are increading, so methods that redice highway closure time are important. There are also many safety issues to be addressed in avalanche control work.

Jan 1, 2002

By Gordon F. Revey

In construction and mining work, situations occasionally occur where hard rock or concrete must be excavated at locations near critical structures or utilities. Fearing damage from blasting, contractors and engineers often explore the viability of using mechanical methods or expansive concrete to facilitate the excavation work. However, for moderate to large excavations, the prolonged duration and high cost of using these methods is often impractical. In these situations, under the right conditions, controlled blasting and blast-management methods can be used to speed up the work and lessen costs. The process of determining whether or not blasting is practical is often complex, particularly when risks are high.

Jan 1, 2002

By Wilfrid Comeau

Vibrograms, which last significantly longer than the actual blast (say 10 to 15 cycles or more), may be signalling an elastic response, which is not uniquely blast related. For example, geophones mounted on a part of a structure, which can elastically resonate at a frequency included in the seismogram, may not show the structure’s real reaction to the blast. This resonance usually amplifies the ground vibration. This contribution examines one particular case where blasting excited and amplified a resonant ground response, and the method used to significantly reduce or eliminate this undesirable condition.

Jan 1, 2007

By S C. Brashear, D A. Anderson, A P. Ritter, S R. Winzer, R Broughton

Results of quarry blasts can be quantified to show the effects of controlled variables. Two studies have been carried out: one to document the effect of delay on fragmentation and the other to show the effects of higher relief patterns and more accurate initiators. By using such techniques as highspeed photography and timing studies of mucking and crushing operations, subtle differences in blasting efficiency can be measured and quarry blasting can be optimized. Given the range of available and developing blasting technologies, quarry operators should resort to quantitative analyses of their blasting practices to get maximum productivity.

Jan 1, 1985

By Kenneth Medearis

The accurate prediction of possible damage to historic structures subjected to blasting-related ground motions is not infrequently the dominant factor in whether or not a mining or quarrying operation is allowed to proceed. A recent scenario involving an 1802 Pennsylvania Historic House was resolved satisfactorily, primarily because of the use of modern structural dynamics analysis techniques rather than simplistic peak particle velocity guidelines. One of the associated dominating factors was the truly significant agreement of the analysis results and the values obtained from actual on-site test shot blast motion recordings.

Jan 1, 1993

By Thomas R. Scotese, John L. Ackerman

The Hanging Lake Tunnel Project represents a major portion of the Glenwood Canyon Project, the last piece of Interstate 70 to be constructed. The project features twin bore, large span rock tunnels and six open cut portal excavations, all excavated by drilling and blasting. This paper presents descriptions of the methods used by the Owner and Engineer to control and monitor the drilling and blasting practices in the tunnels and in the portal areas.

Jan 1, 1992

By Jerry R. Wallace

Infrastructure improvements and industrial plant expansion and modernization often require rock blasting within 20 feet of existing structures. In many instances trenchlines must cross beneath existing in-serv1ce utility lines.

Jan 1, 1994

By Paul D. Dupree

This paper discusses the drilling and blasting techniques used in blast casting at a large western coal stripping operation.

Jan 1, 1986

Lightning Strikes on Vehicles Transporting Explosives The police in one of the countries in which we operate has asked about the consequences of a lightning strike on a vehicle (box van) carrying detonators and explosives. We have assured them that there is not a problem but they require proof of this.

Jan 1, 2011

By Rowland Jones

This type of quarrying is very much different from that of established quarries in developed countries, demanding somewhat unorthodox techniques to produce the variety of materials required. The demands on the resourcefulness of-the quarrymaster can be very testing, and produces quite a different breed of individual than what is normally met in managerial status in quarries of developed nations.

Jan 1, 1977

Blast performance is related to rock structure and strength, as well as to factors such as site geometry, drill patterns, explosives loading, firing sequences and delays.

Jan 1, 1986

By J S. Brower

Disposing of the AMDP-1, Jackup drilling rig in the Arabian Gulf.

Jan 1, 1978

By Tom Medak, Don H. Cranney, G Paul McKay, R Douglas Reid

Explosive initiated afterblast dust explosions can occur in high sulfide ore mines when the flame generated by the detonating explosives ignites the sulfide dust produced from the blast, from previous blasting, or from other mining activities. The dust explosion can be a devastating, self-propagating fireball that will damage or consume any flammable object in its path. Damage to ventilation tubing is a frequent occurrence. These explosions also produce large quantities of sulfur dioxide and other noxious gases that can take several hours to clear from the mine. Thus, these occurrences can result in substantial losses in productivity to the mine.

Jan 1, 1994

By Tom Watts

The practice of pumping bulk blasting agents is regulated by many agencies around the world. The explosives manufacturers have done an excellent job of hazard and operability studies allowing criteria to be established for the safe pumping of water based blasting agents. The challenge of a Bulk Trucks or Mobile Manufacturing Units (MMUs) manufacturer is to take the objectives of the regulatory agencies and the explosives manufacturers and responsibly design and build MMUs that are safe, compliant, and cost effective without compromising serviceability.

Jan 1, 2011

By Bryan Papillon, Karl Christopherson

In order to improve vibrations from quarry blasting, a new technique and timing pattern was established and applied to the particular geology. By shooting a single representative borehole one full second ahead of the production blast, a signature waveform can be isolated and analyzed. Multiple productionsignature blasts were performed. Encroaching residences require quarries to adjust their blasting techniques to reduce vibrations and raise frequencies. A signature hole inherently poses problems to quarries. Blasting one single hole from a production bench poses safety issues to wall stability; vibration issues to close neighbors; and budget issues to the quarry operator. Results showed that the new timing pattern reduced vibrations through timing optimization without a loss in quarry production. Therefore, this technique of vibration analysis employing a production-signature hole is successful in creating a timing pattern that meets the quarry’s goals.

Jan 1, 2008

By Takeo Ueda, Masashi Nakano

We have developed a new blasting system remotely controlled by an electromagnetic firing method, which has proved advantageously applicable to sites where rapid tidal current or deep water may cause serious troubles in underwater blasting operation by a conventional method.

Jan 1, 1983