Search Documents

By Donelson A. Robertson

Proper coupling between the seismograph transducer and the surface is the most important aspect of seismograph monitoring but probably receives the least attention in many blasting situations. Without good coupling, particle velocity measurements may be higher than actual and frequencies may be lower. If the field data are inaccurate, sophisticated instrumentation and computer programs cannot correct the readings.

Jan 1, 1993

By Wiliam Reisz

As we approach the peak season for thunderstorm activity it’s important to keep in mind that lightning still poses a serious threat to drilling and blasting operations. Lightning remains the number one cause of accidental detonation of explosives.

Jan 1, 2008

By Dale Nies, David P. Childs

The open pit gold and silver mining operations in the State of Nevada have historically used simple row by row, echelon, or chevron delay patterns. Common practice has been to use detonating cord trunklines and either detonating cord downlines or nonelectric common in-hole delays in conjunction with surface delays. Several operations use a series of downhole nonelectric delays with an entire row loaded with the same delay to develop similar patterns.

Jan 1, 1991

By Magnus Gynnemo

The primary purposes of drilling and blasting in hard rocks is to fracture solid rock and prepare it for excavation and subsequent transport to the crushing plant. Using explosives in excavation operations without counting for the geology gives no consideration to the quality of the macadam product or the excess production of waste material (fines).

Jan 1, 1997

By Jaime Huidobro, Michele Hall

The desensitization of an explosives column by the transmitted effects of the earlier detonations in nearby explosive charges is of vital concern to the explosives and blasting industries. Stress waves from detonations of borehole charges have the capacity to desensitize adjacent delayed borehole charges. This desensitization can be of a transient or a permanent nature.

Jan 1, 1994

By Mauro Fornaro, Marilena Cardu, Renato Mancini

Detonating cord cutting is widespread in dimension stone extraction, especially in the case of hard, abrasive stones as granites, an important resource for Italian industry. General data on this production sector are briefly discussed and analyzed in the first part of the paper. The theoretical basis of operation are summarized, and compared to data obtained from selected commercial cases, in the second part.

Jan 1, 1994

By C F. Argo

In the past several years the "Kelly Bar", an innovative device, which incorporates borehole d-rifling and explosives loading into a single detail, has come under scrutiny and criticism. The practical aspects of the Kelly Bar procedure is not questioned, and the system has been highly successful in expediting the loading of explosives in difficult and unstable formations. There have been a number of accidents indirectly associated with Kelly Bar loading and the point in question has become one of safety rather than mechanical feasibility.

Jan 1, 1975

By Calvin L. Cumerlato, David E. Siskind

The Bureau of Mines has monitored structural responses to airblast overpressure produced by munitions disposal at the McAlester Army Ammunition Plant. The Purpose of this study was to determine if the blasting caused vibrations, airblasts or structural responses that could possibly be responsible for cracking or other damage observed in nearby residences. Monitoring took place during a 3-month period at 10 selected residences surrounding the plant. By the end of the monitoring period, nearly 2300 blast-related events had been recorded.

Jan 1, 1994

By Mike Cammack

Western South Dakota is predominately an agricultural area, with exception of the mining and timber industries in the Black Hills region. With precipitation rates averaging below fifteen inches per year, water is a precious commodity to the livestock industry. There is a constant demand for the construction of earthen water storage facilities (dugouts) to catch snow and rain runoff, or developing natural springs.

Jan 1, 1993

By James Barker, David Leidel, Don Crawford, Daniel Dorffer

This paper describes the test processes performed to ensure the suitability of an RF-safe detonator for use in oilfield explosives operations on land and offshore locations where RF silence cannot be implemented or the distances from explosive systems arming operations to the RF source or sources are too close for conventional resistorized hot-wire detonators based on the safe distance tables. The test program for the detonator assembly was based on MIL-STD-461E, “Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment”, 20 August 19991.

Jan 1, 2008

By Joe Sr Strobbe

In 1933 the Cobre Mining Company re-opened the 32-year-old UV Industry Mine, which is located in a scenic canyon near Silver City, New Mexico. The site location is shown in Figure 1. Current mineral extractions are copper and magnetite; both extractions similar to those mined many years ago. Copper is extracted from chalcopyrite imbedded in the host rock of massive limestone deposits and magnetite, an iron ore, is a by-product of the same extraction process.

Jan 1, 1998

By John W. Kopp

The U. S. Bureau of Mines investigated flyrock and burden movement from blasting at several limestone and basalt quarries in the upper midwest. Blasts have been studied at 14 different sites using high-speed cinematography. Blasting was accomplished in 75- and 150-mmdiameter holes using a variety of explosives. Films from each blast were analyzed to show burden velocities, observed flyrock distance, and direction of throw in relation to the shot layout. This technique, in some cases, allowed determining point of origin and cause of the flyrock as well as the flyrock range.

Jan 1, 1994

By John F. Mitchell

Large production blasts involving many series in parallel have long been a source of complication. When speed and accuracy are most necessary in blast preparation an efficient and precise method of wiring is required. After loading a large number of holes and being pressured for time, due to lack of daylight, equipment shutdown, etc., an effective hook-up plan can eliminate many last minute problems. It is the intention of this paper to offer a simplified wiring proceedure which when employed can save precious time and encourage efficient and economical utilization of blasting personnel and material.

Jan 1, 1976

By Christoper J. Hunter, Tony Mansel, Carl Kolada

With a current trend toward Bulk Mining methods utilizing both large diameter uphole and downhole drilling, corresponding loading equipment and technology is required to safely and efficiently load these blastholes. Such is the case at Inco Limited Thompson Mine.

Jan 1, 1990

By Charles H. Dowding

This paper describes NUVIB, analytical software to digitize, analyze, display, and plot time histories generated by blasting and construction vibrations. It is available in conjunction with a new book on Construction Vibrations (Dowding, 1996) through internet procedures described at the end of the chapter on analytical software These internet based procedures eliminate the need for inclusion of disks in the book and take advantage of the growing electronic communications network. Perhaps more importantly this procedure allows the software to be updated more often than the book is reprinted.

Jan 1, 1997

By William B. Lee, James J. Jurmu

The Cleveland-Cliffs Iron Company operates three open pit iron mines on the Marquette Iron Range of Michigan's Upper Peninsula. Open pit iron ore mining began in the area in the 1840's. Underground mining was predominant from 1860 through 1960. Large scale low grade-open pit iron ore mining began in the early 1950's with the establishment of the Humboldt Mine, concentrator and pelletizing plant. This pit operated until 1970, when the reserves were exhausted.

Jan 1, 1986

By Lee W. Saperstien

Section 709 of Public Law 95-87, "Surface Mining Control and Reclamation Act of 1977," requests the National Academy of Sciences to determine if the standards of the act are applicable to minerals other than coal. The Academy has established the Committee on Surface Mining and Reclamation to respond to this charge. The committee is, itself, organized to be responsive to the varieties of minerals, environments, mining systems, and locations that are representative of U.S. mining systems. It is not the charge of the committee to write trial legislation, but to indicate whether or not technology, extant or proposed, is available to meet the standards of the law, and at what cost. It is within this set of conditions that the committee will examine blasting.

Jan 1, 1979

By J Edmund Hay, T S. Bajpayee

The Bureau of Mines is developing a test to determine the initiating strength of commercial detonators. Various tests of "detonator strength" are in use, but many of them do not correlate well with each other, and so far, there is little evidence that any of them correlates well with the ability of detonators to initiate detonation in an explosive. Therefore, the Bureau decided to attempt a measurement of the ability of detonators to initiate detonation. To this end, an explosive mixture of adjustable sensitivity was developed. This mixture was nitromethane sensitized with ethylene diamine, the sensitivity being "fine-tuned" by the addition of nitropropane.

Jan 1, 1992

By William R. Adamson, Carlos R. Scherpenisse

The successful development of surface mining operations depends, amongst other factors, on the successful creation of final pit walls which offer long term structural stability. The achievement of such walls will be much more feasible if the mechanisms of rock mass deterioration in the mine are well understood, permitting the control and reduction of this deterioration (or damage). The role of drilling and blasting in causing damage is widely accepted but rarely fully quantified. It is also true that the dependence of rock mass damage on vibration levels is only incompletely understood and little accurate field measurement is routinely conducted in the mining industry.

Jan 1, 1998

By Kunihisa Katsuyama, Yuji Ogata, Takuya Taguchi, Toshinori Arikiri, Yuji Wada, Kiyoshi Hashizume

The impact sensitivity of hot emulsion matrices was examined to investigate the safety assessment in the emulsifying equipment which forms the emulsion matrix in a water-in-oil type emulsion explosive. The sensitivity could not be evaluated by the small fallhammer test device commonly used in Japan. Therefore, a large fallhammer test device was used. It was confirmed that an explosion, a decomposition, or a no-reaction took place according to the degree of the impact. When a decomposition took place in the hot emulsion matrix, the behavior of it was investigated further by a DDT test. It was found that a decomposition, or a no-reaction occurred according to the degree of confinement.

Jan 1, 1997