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By Tristan Worsey, Nathan Rouse

The Florida legislature allocated funding for the Florida State Fire Marshal (FSFM) to review the applicability of the United States Bureau of Mines (USBM) Report of Investigations (RI) 8507 blast vibration limits with respect to Florida and its soils. The study also discusses whether the current blasting vibration limits set by statute are still appropriate, including a review of measured vibration amplitudes and frequencies, structure responses, and theoretical analyses of material strength and strains

Jan 1, 2019

By Quentin Rhoton

To benefit two endangered fish species, waterfowl and other wildlife, and water quality in the lake and downstream, the decision was made to remove levees that had been in place since the 1950s. Because the levee material was mainly dredged up lake bottom peat, it was decided to pare down the sites chosen for breaching with dozers and trackhoes. This material was spread out onsite instead of expensive removal by dumping elsewhere. Because of the instability of the final pared down levees and the lake level being at a ten-year low, it was decided to use explosives to breach four of the sites. After over five months of earthmoving and two weeks of loading holes, the levees were detonated the day before Halloween, 2007. Somehow pumpkins showed up to be part of the explosive activities.

Jan 1, 2009

By Robert B. Hopler

The hazards which naturally prevail in underground coal mines, always severe and unpredictable due to the loosely-consolidated strata in which coal is frequently found, are increased by the commonly-occurring combination of coal dust, methane, and explosives. It was recognized by the mid-nineteenth century that coal dust was the basic factor contributing to disastrous explosions killing hundreds of miners, and that the ignition of methane gas was often the source of the coal dust explosions. It was apparent that preventing the ignition of methane was a critical part of avoiding these disasters, and it was also apparent that one cause of such ignitions was the firing of explosives. In addition, it was found that dust explosions were often initiated by blown-out shots of explosives in the absence of methane.

Jan 1, 1996

By Robert B. Hopler

Emplacing explosives in the borehole by bulk methods is utilized today for about 35% of all of the explosives used in the United States. Although different from today's methods, some bulk emplacement has been utilized throughout the history of explosives. This paper provides an overview of the evolution of the industry from primarily packaged to primarily bulk materials and methods.

Jan 1, 1992

By D S. Preece

The aim of the present work is to investigate the effects of shooting multiple explosive charges, in the same borehole, on the amplitude and frequency content of the generated seismic wave. The work also investigates the effect of the coupling medium used in the borehole on the quality of the generated seismic wave. The delay period between the shots is on the order of months and up to a year. The investigation utilizes a numerical modeling approach which is capable of modeling the detonation of explosives as well as shock and stress wave propagation in solids.

Jan 1, 2012

By Jena Moshen

Underground Bulk Systems (UBS) technology has gained widespread application in tunneling and underground mining owing to its safety, reliability, increased Velocity of Detonation (VOD) and excellent results. However, its application in perimeter blasting is still limited and researchers are looking at ways of harnessing this technology for perimeter control. This simplifies the charging process by using one cost efficient product for charging both the perimeter and grid holes. This paper presents a case study on the application of underground bulk emulsion explosives for perimeter control blasting in underground room and pillar platinum mines. In order to achieve the required coupling ratios in the perimeter holes, the emulsion is loaded into specially formulated smaller diameter polyethylene (poly) pipes. The effectiveness of this method was evaluated using information obtained during routine blast audits and data supplied by the mines on half cast factors, over break and under break as well as analysis of data from Ground Penetrating Radar (GPR) Scans over a period of four years. This method of perimeter control, has given the platinum miners in Zimbabwe a competitive edge in cost effective perimeter charging and blasting by simplifying the previously costly deployment of traditional barrels and other decoupled cartridges. The method has been adopted by all the platinum mines in Zimbabwe as it has proven to be a cost effective alternative of controlling the perimeter walls, along with other key benefits that relate to safety, productivity and effectiveness.

Jan 1, 2018

By Kyle Wagner, William Joa, Colter Angell, Catherine Johnson, Marty Langenderfer, David Doucet

The goal of any business is to seek the maximum profitability for the organization through optimization the use of resources, processes and the application of new technologies. An analysis of various case studies demonstrate that blasting can have positive impacts on the crushing and milling processes resulting in increased profitability for the mining industry (Grundstrom, Kanchibotla, Jankovich & Thornton, 2001). This paper describes the case study of two copper mines in Peru producing Cu-Mo and Cu-Au concentrates, which together with their strategic partner, have implemented a project focused on the improvement of rock fragmentation. The project was based on techniques of pattern size reduction, the use of high energy explosives and the technology of electronic initiation. Combined, these techniques were shown to have significantly impacted the efficiency of downstream processes.

Jan 1, 2019

By MacDonald B. Johnson, Douglass P. Bacon

"W ith the advance of science, rise of public interest in environmental matters, and continuing erosion of air quality, federal and state regulators are demanding an increasing complex array of data concerning emissions produced by burning and detonating energetic materials. The U.S. Department of Defense, one of the world’s largest consumers of energetic materials, now must characterize combustion products resulting from open burning/open detonation disposal operations. The catch-all phrase “below detection limits” no longer satisfies the regulators who nowwant testing to delve into the ppt level for volatile organic compounds and ppt level for semivolatile organic compounds."

Jan 1, 1995

By Chris Breeds, Ken Johnston, Omar Fulton

This paper describes the process typically involved with obtaining permits for quarry blasting in urban, suburban, and rural areas, including: content of SEPA (State Environmental Policy Act) driven documentation; regulatory review and comment; public interaction; public hearing(s); periodic regulatory review(s); negotiated solutions; monitoring; and the role of public interaction, demonstration(s), and education in the process. Case studies will be presented of projects undertaken in the State of Washington that illustrate the approach and regulatory interaction as well as the importance of public interaction throughout the process. Reference will be made to the role of national and state regulations and local codes and ordinances that provide additional limitations on blasting practice. The paper will also present regional blast monitoring data that are used in the permitting process and the layout and design of blast monitoring systems typically required as conditions of the quarrying permit. Our presentation will include tools, which we have developed to assist with explaining blast related phenomenon to both regulators and the public.

Jan 1, 2003

By V. A. Akinbinua

This work is intended to examine the relationship between rock fragments produced during compression tests using a soft testing machine, e.g. hydraulic press (the machine used in this work is Amlser rock testing machine), and the rock fragments size distribution produced by fragmentation of the same rock through application of explosive. The rocks tested are fine grained marble, medium grained tonalite and fine-medium grained granite, medium grained norite and medium grained gabbro. The rocks types are prepared according to ISRM methods to be tested for strength determination. The rocks are loaded at constant load until failure. The fragments resulting from the failure of each of the rocks types are collected for size characterization by sieve analysis. The same rocks tested under soft testing machine are also prepared into blocks of dimension 150 mm length x 100 mm width x 100 mm height for blasting by explosive application. Each block of the different rocks are drilled through with an 8 mm diameter drill to a depth of 80 mm. Each of the holes on the blocks is spaced from each other at 44.7 mm and with a burden of 28 mm. The holes therefore formed a rectangular blasting pattern. Each of the holes was charged with a 720 mg electronic detonator and fired instantaneously inside a cylindrical blasting chamber. After each shot, the fragments are collected for size characterization. The sizes distributions from blasting are compared with sizes distributions resulting from rock testing using the parameter Xc of the Rosin-Rammler distribution function (RR) and 75% cumulative percentage passing. The analysis and finding from this work is presented in this paper.

Jan 1, 2014

By C. Pelley, S. Kelebek, S. Gregersen, P. Katsabanis

A series of small scale tests have been conducted to evaluate the effect of micro-fracture development, imposed by blasting, on the physical properties of the rock as well as its resistance to crushing and grinding. The uniaxial compressive strength, tensile strength, Young’s modulus, Poisson’s ratio, P-wave, S-wave velocity, point load strength index and grinding work index were evaluated for samples without any blasting load and for samples which had received a variety of blast loads, such as a simple side impact from a detonating cord, or combined impacts without any delays and with very short delays. The investigation covered two types of rock, granodiorite and limestone. The effect of blasting load on the physical and rock mechanics parameters of the rock was clearly shown and damage was quantified and related to loading. However the work index did not show significant differences between blasted and not blasted samples, probably due to the relatively low level of impact. Numerical modelling using the AutodynTM code was used to demonstrate damage development in the various configurations tested.

Jan 1, 2003

By Steve Colburn

The CRITERION Survey Systems utilize both theodolite mounted and hand held reflectorless distance meters. These are eye safe, easy-to-use, and specifically designed to endure the harsh environments characteristic to the mining, quarry and explosives industries. Survey data collected by the systems is digitally stored in a ruggedized data collector and then processed with a specialized, Windows-based, interactive software program which can be run on’ any standard PC.

Jan 1, 1998

By Tom Treleaven, Andrew Williams

Several contracts were let in Greenwich, Connecticut, for the installation of a sanitary sewer. The majority of the excavation was in rock and involved numerous challenges due to the following conditions:

Jan 1, 2003

By K B. Holm

This paper deals with the advances made at Syferfontein Colliery in the calculation and control of dragline methodology. The high capital outlay and operating cost of a dragline necessitates strict control of all aspects of the dragline operation. Before purchasing a dragline, a complete evaluation of all the parameters that can affect the viability, now and in the future, of the dragline operation needs to be completed. Such parameters as thickness of burden, material properties (swell), “castability”, pit width and pit length, etc. need to be considered.

Jan 1, 1994

By Steven A. Mathe, Seokbin Lim

Current analytical models can accurately predict the final velocity of explosively driven flyers and can somewhat predict the acceleration profile, but do little to address the deformation of the flyers. Explosive systems such as linear shaped charges and explosively formed projectiles, which can be described as multiple interacting explosively driven flyers, often involve interactions between the flyers that occur much before the flyers reach their predicted final velocity. In this regime, it is important to accurately understand both the acceleration profile and the deformation profile of the flyers, as both significantly affect the functioning of the explosive systems. Previous work proposed an analytical model to meet this need. As the expanding gas cloud of detonation products drives the flyers, rarefactions impinge upon the gas cloud from around the flyer edges, which produces a pressure difference across the back face of the flyer leading to deformation of the flyer. Previous research condensed the effects of the rarefactions into a single term, the pressure release ratio, ?, which was calculated based on hydrocode simulations of a block of explosive only and an assumption of isentropic expansion. This work intends to determine the value of ? for different explosive compounds. The results of this analysis were compared to hydrocode simulations of an open-faced sandwich configuration explosive/flyer system with an average accuracy of 15% across the tested compounds.

Jan 1, 2015

By John Babcock, Gregory Poole, Ron Hudson

In January 2007, Fultondale Alabama opened a new elementary school. Site work at the old school location included blasting activities and the old school building was scheduled for demolition. With help from Apache Construction, blasting was scheduled to be performed in close proximity to the old school building prior to the demolition. Arrangements were made to perform extensive monitoring on the old school building during the blasting activities. The monitoring plan for the project included: • Pre and post blast inspections were performed on the structure; • Conventional crack monitors were installed at 22 locations throughout the structure; • Digital displacement monitors were installed at 6 locations on the structure; and • Seismographs were used to monitor structure vibration at 6 locations and ground vibrations at 9 locations. Blasting activities were allowed to produce vibration levels well above the safe levels established by the U.S. Bureau of Mines (USBM). Vibration levels up to 7.44 in/sec were recorded with no damage noted. Permanent deformation was recorded on vibration levels of 9.68 and above. Not only did this project reinforce previous studies which indicate that concrete block walls can withstand vibration levels well above 2.0 in/sec, this study was also a good example of employing new technology to help determine if/when damage occurs on a specific structure.

Jan 1, 2009

By Ettore Contestabile, Cameron Thomas

Implosive connectors such as XECONEXTn have been used extensively for joining electrical conductors. This implosive action of explosives has also been used in other forms of high-energy metal working with excellent results. However, the inherent blast energy of these units can cause environmental side effects (especially airblast) which may restrict their use around inhabited areas.

Jan 1, 1994

By P D. Katsabanis

According to Persson(1) steady state detonation along a cylindrical charge can be regarded as a self propagating process in which the axial compressive effect of the shock front discontinuity changes the state of the explosive so that exothermic reaction sets in with the requisite velocity.

Jan 1, 1989

By Qi Shifu, Guo Tao, Liu Haoquan, Yao Chaogui, Zheng Li

Abstract: To excavate oil-gas pipeline ditches in a rocky region or area the explosive method is needed. When a parallel ditch is to be dug by blasting near or in the vicinity of an existing pipeline, a safe criterion must be determined to ensure safety for the latter. In this investigation, with the construction of the second phase of the West-East Gas Pipeline Project, we carried out real blasting tests and numerical simulations to explore the safety criteria for the existing pipeline. Through this investigation, we obtained the safe strain elasticity threshold es2000µe, blast vibration velocity calculation formula, and the maximum vibration velocity Vmax=14cm/s(5.51in./s) for the pipe under blast shock loading, and worked out how to determine the charge size in the follow-up blasting excavation. These results can be used to determine the maximum explosive weight per delay and decide delays for the initiation circuit network in blasting a parallel pipeline ditch, and to make safety assessments for the existing pipeline in service. Having successfully been applied in the second and third phases of the West-East Gas Pipeline Project, China-Russia Oil Pipeline Project and China-Myanmar Gas Pipeline Project, these findings are very significant for other similar pipeline construction.

Jan 1, 2014

By Noel Dent

Increasing interest is being expressed in the development and availability of Electronic Delay Detonators throughout the world. Particularly in open-cast mining, the benefits associated with precise, reliable initiation systems are perceived to be considerable. Many of the systems currently being developed have sophisticated programming requirements associated with them, or are numbered systems that require predetermined layouts to determine timing patterns, and importantly are far more expensive than existing initiation systems.

Jan 1, 1994