Search Documents

By Joshua Micah Hoffman, Catherine E. Johnson

The recruitment and retention of future talent into the explosives industry is becoming increasingly important. One potential area from which future talent can be recruited is local student chapters. Many of the student chapters are closely connected with engineering programs. While this makes sense and both entities benefit from these arrangements, there is a trend of job placement primarily in the engineering industry. Before the explosives industry can begin to compete with other industries, it should be determined what is drawing the students into these other fields. The work presented in this paper sought to better understand the collegiate student population from which a portion of future explosives professionals will emerge. This was done through the use of an anonymous online survey distributed to the student members of the International Society of Explosives Engineers, as well as, members of SEE student chapters. The survey contained questions about future job and career plans, ideal job placement, and expectations of salary. The purpose of the survey was to determine what these students expect or require from a career in the explosives industry. This information can help steer recruitment activities and job offers. Through understanding what is incentivizing these students who have accepted or plan to accept jobs in other industries the explosives industry can better posture itself to be more competitive in recruiting from the collegiate talent pool.

Jan 1, 2014

By Stanley J. Vitton

An important factor to consider during blast damage investigations is whether the structure was constructed on collapsible soils. Traditionally, these soils have been considered to be soils such as loess deposits, which occur along the Mississippi River in locations such as Vicksburg, MS. However, recent research into collapsible soils has indicated that a number of soils may also fall into this category. A collapsible soil is any soil that is susceptible to large decreases in bulk volume upon saturation.

Jan 1, 1997

By Joshua Hoffman, Catherine Johnson, Braden Lusk

The practice of dual initiation using precise timing from electronic detonators in boreholes is thought to be beneficial for increasing fragmentation at a desired location in the rock strata. This increased capacity for fragmentation is understood to be a product of both the collision of detonation waves in the explosive column and an increased energy liberation rate, each resulting from dual initiation. In addition, the collision of shock waves from two adjacent blast holes is suggested to improve fragmentation at the location the two shock waves meet, which can be controlled with precise timing. This paper presents the results from scaled laboratory experiments where converging detonation waves and shock waves were studied.

Jan 1, 2014

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 Clifton W. Livingston

This paper is the first of a series in which evidence suggesting a quantum mechanical behavior of materials in blasting and high energy impact loading is presented. Such evidence relates the mechanical behavior of materials to their electro-magnetic behavior at successive stages in the development of the electric and magnetic fields as the disturbance proceeds outward from the borehole in blasting.

Jan 1, 1981

By Carl R. Peterson, Robert G. Lundquist

The development of a remotely-controlled drill and blast excavation system is desirable both because it is potentially more economical than mechanical tunneling in hard rock and for safety. A serious impediment to such development is the problem of relocating and reentering previously drilled blast holes to place the explosives.

Jan 1, 1983

By Luiz Felipe Mendonça de Amorim, Adimir Fernando Rezende, Gustavo Sampaio Lopes, Claudio Cesar Gajardo Arraño, Eltton de Sousa Veras, Manuel Villalobos Calderon

Many technical challenges were encountered while conducting near-field construction blasting between the critical intersection of Interstate 10 and multiple active railroad tracks in El Paso, Texas, for the Loop 375 Border West Expressway Project. Blasting was utilized for the removal of an andesite bedrock ridge in preparation for the construction of a new elevated super structure to be suspended over the existing railroad tracks. There was concern that the excessive vibrations and/or permanent rock deformation produced from the blasting within near proximity (20 feet, or 6.09 meters) of the railroad tracks would induce excessive stress and foul the tracks by shifting the alignment. This could result in a major loss of scheduling control between the two major railroad companies that operate in this area. There was also concern that the blasting may cause rock fragments to land on and interfere with critical interstate transportation. Blasts

Jan 1, 2019

By Duane A. Houkom

Explosive demolition of concrete has been accepted as a safe and economical means of concrete removal for many years. I imagine that the early concrete blasters were experienced rock blasters who applied their knowledge to just another formation. Since a concrete foundation is generally located in a congested area, the owner is willing to accept the higher costs of mechanical removal,rather than promote "a new idea" to his management. This attitude is rapidly changing,making it possible to use the advantages of explosives in more congested locations.

Jan 1, 1982

By James E. Jr Hargroves

With the ever-increasing population growth and modern trend to urban development, the expansion of utilities is a stable, mad or, and constant source of income for many. Blasting is a "necessary evil" to the utility contractor. It can make or break even the most solvent. Housing development expansion and higher treatment of effluents are causing utilities to appear in more congested areas. This paper discusses some of the aspects of utility blasting in the State of Virginia. Consideration is given to bid procedures, pre-blast surveys, record-keeping and practical application.

Jan 1, 1977

By Paul Worsey, Matthew Coy

In the blasting industry, many different techniques are used to estimate and examine the effects of varying explosives and blast designs on the breakage of a rock mass. The overall objective is to find a cost-minimized blasting solution that also conforms to the legal and environmental concerns related to blasting. A major drawback to current blasting methods is the inability to account for "caprock," or a thick overlying layer found in sedimentary rocks that creates large amounts of oversize blasted material, especially on the top of a muck pile. This can lead to underestimating oversize in shots with massive top layers. A better fundamental understanding of blasting processes with caprock is required.

Jan 1, 2018

By Art Frye, Lee Pratt, Gaichang Zhao, Greg Newman

This paper will discuss the Wight Pit wall slash at the Mount Polley open-pit copper-gold mine that scavenged a high grade block of ore from two double-benches of the pit wall. The Wight Pit orebody, discovered in 2003, is located in the Northeast of the property with the southeast pit wall approximately 50m (165ft) from the edge of Polley Lake. In early 2009, the Wight Pit was nearing completion while an estimated 150,000 tonnes (165,000 tons) of ore averaging a grade of 1.4% copper remained just inside the southeast pit wall. The ore block started 24m (78ft) above the pit floor and extended up another 48m (157ft) with a 70o plane defining the back of the block.

Jan 1, 2011

By Cathy McGinley, John Mullay, Clark Stancavage

The use of crater studies to evaluate explosive performance is a well-established practice in the Blasting Industry. Normally, this work utilizes larger charge sizes (>75mm) in order to minimize the influence of geological factors adjacent to the borehole. This can impose unwanted restrictions in the experimental factors accessible to investigation. Thus, for example, systematic studies of non-ideal performance in a somewhat practical setting is rendered quite difficult.

Jan 1, 1995

By GF Brent, Armstrong L. W

It is recognised that presplitting is a special case in blasting which requires the reduction of conventional explosive pressures in order to avoid excessive rock damage. Two routes to achieving this are the use of reduced density explosives or the practice of decoupling the explosive from the blasthole walls. Applications of two such systems in large diameter, deep blastholes are described. Both systems were tested in presplits alongside sections charged with decks of conventional explosives.

Jan 1, 1998

By John Floyd, Larry Wardrip

A series of tests were conducted to evaluate the performance of a high density, high velocity cartridged explosive. The tests included two production blasts in a limestone quarry and two production blasts in a granite quarry. To quantify blast and product performance, each blast was monitored with the following equipment: l Two (16mm (Lo Cam) high speed cameras (500 images per second) l Velocity of detonation recorder (I million samples per second) l Four face motion accelerometers (1 million samples per second) l Digital seismograph The fragmentation distribution produced by each blast was quantified with digital image analysis The benefits of the use of high velocity, high density toe loading was quantified in terms of: l Vibration reduction l Fragmentation improvement l Excavator performance In addition to the field tests, a comprehensive evaluation was performed to determine the cost/benefit relationship of the use of the toe load. This paper will include the findings of the study along with guidelines for use in other quarry operations.

Jan 1, 2002

By Larry Mirabelli, Gerard J. O'Brien

"The construction of the Third Harbor Tunnel is a key element of the Central Artery TunnelProject. The tunnel is to traverse Boston Harbor directly linking South Boston to EastBoston. The tunnel is a cut and cover tunnel as opposed to a bored tunnel. The cutdimensions are 95' wide, 110' deep and approximately 4000' in overall length."

Jan 1, 1993

By Ruilin Lang

This paper presents an application of 3-D plots and non-linear regressions to define a sitespecific form of the charge weight scaled distance. The PPV (PPA) of single hole blasts is normally considered as a function of two independent variables - the charge weight and the distance. It is of great importance to obtain the relationship of the function accurately for a concerned site in terms of blast vibration analysis and modeling. However, in pre-computer time it was difficult to plot 3-D graphs. Consequently, a charge weight scaled distance was used to plot the PPV (or PPA) against the scaled distance as 2-D graphs. Blast vibration investigators use several forms of the charge weight scaled distances to plot data. We can exemplify them with the cube root of charge weight scaled distance, the square root of charge weight scaled distance, and other forms (Hossaini and Sen, 2004). Each of these scaled distances assumes relative contributions of the charge weight and the distance to the vibration attenuation. For example, the charge weight is assumed to have a less contribution to vibration in the cube root scaled distance than it is assumed in the square-root scaled distance. In reality, for different sites the relative contribution of the charge weight and the distance may be different and site-specific. This may explain that in some cases, the blast vibration data plots using these charge weight scaled distances are scattered. This could be largely due to the fact that the definition of the form of the charge weight scaled distance is not adequate for the particular site condition.

Jan 1, 2006

By S R. "Bob" Pilshaw

Productivity is the popular "buzz" word that catches the attention of most managers when it is featured in the more popular mining and construction magazines. Engineering Task Forces and teams are formed to take advantage of productivity opportunities in almost all phases of an operation except the drilling and blasting area.

Jan 1, 1988

By Jack C. Leader

The success of a blast using ANFO in wet boreholes is dependent on the quality of the bag the ANFO is packaged in. When a shot fails the dragline may stop and expensive redrilling may be necessary. The total loss to the mining operation can be hundreds-of-thousands-of-dollars.

Jan 1, 1981

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 J Lyall Workman, Peter N. Calder

Large hole rotary drilling is one of the most common methods of producing blastholes in open pit mining. Large hole drilling generally refers to diameters from 9 to 17 inch (229 to 432 mm), however a considerable amount of rotary drilling is done in diameters from 6½ to 9 inch (165 to 229 mm). These smaller diameters are especially prevalent in gold mining and quarrying.

Jan 1, 1996