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By Karl Ingmarsson

A model for drilling productivity and total drilling cost is presented. It specifically addresses down-thehole drilling, but also covers other drilling methods. The important factors are: 1, productivity in tons drilled; and 2, total cost per drill ton. For non-blasthole applications these factors are measured in drill feet and cost per foot. The model focuses on the entire system and allows the operator to optimize the system based on individual drilling conditions.

Jan 1, 1998

By J R. Phin

The properties of all available modern blasting initiation techniques are reviewed. Primadets are nonelectric initiators, the nonelectric features of the system eliminates concern of premature initiation from static or stray currents. The loading techniques are simple and a minimum of training is required. There is no limitation in the number of necessary sequences in which the Primadet need be connected for initiation. This flexibility improves vibration control,and often reduces costs due to increased fragmentation.

Jan 1, 1975

By Adrian Moore, Alan Richards

A real-time system for prediction of the effect of meteorological conditions on airblast overpressure levels has been established in the Hunter Valley Coalfield in Australia. Real-time meteorological data from continuously operating sounding equipment and a predictive meteorological model is input to an atmospheric refraction model that enables the effect of meteorology on airblast overpressure levels in the area surrounding the blast site to be evaluated. Graphical outputs from the model, which are superimposed over a scaled airphoto of the mine and surrounding area, show the extent that airblast levels will be increased. When combined with inputs that quantify the effect of blasting specifications, the airblast levels that will result in the surrounding area from the combined effect of blasting specifications is determined. The model permits those responsible for blasting to make more accurate decisions on suitable times that blasting may take place to conform with applicable airblast limits.

Jan 1, 2009

By Guang-Xin Li, Rui-Ping Guo

Based on the analysis of factors affecting the cracking performance of Silently Cracking Agent (SCA), a new SCA structural model is built and a study on the swelling mechanism of SCA and a method to increase swelling thrust by adding the swelling agent are presented. The reason for blow-out and the theory for avoiding blow-out are put forward. The new model improves the SCA theory and provides new method for developing effective SCA. Based on experiments made in laboratory, two types of SCA are developed. A Temperature Control Meter (TCM) has been developed to solve the alltemperature- crack problem after studying the suitable temperature scope of SCA.

Jan 1, 2000

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 Harry Verakis, Thomas Lobb

A great deal of information has been presented and published on the danger from flyrock created from blasting operations. The creation of flyrock is not specific to any one blasting operation. Flyrock is certainly not a stranger to blasting operations conducted in the mining industry and its effects are well known. Flyrock is among the leading causes of mine blasting injuries. Awareness and diligence is the message that must continue to be stressed and followed to reduce the potential for creating flyrock from blasting operations and to reduce the hazard it presents. A recent accident that resulted in a serious injury at a limestone mine in Pennsylvania bears witness to the ever-present danger of flyrock created from blasting operations.

Jan 1, 2007

By David Harrison

The Charleroi Locks and Dam (Figure 1) was completed in 1932 and is located on the Monongahela River, approximately 22 miles (35 km) south of Pittsburgh, in Charleroi, Pennsylvania. It is comprised of a 420 foot (128 m) gated dam, and a 720 foot (219 m) by 56 foot (17 m) land side lock which provides for a 16.6 foot (5 m) vertical lift.

Jan 1, 2015

By Robert Jacob Cefalo, Rio Tinto Kennecott

At the end of 2016, the Mine started a new ore phase in the section of the pit located on the East Wall. The East Wall geological structures required controlled blasting for peak particle velocity (PPV) frequency vibrations to protect the wall. Frequency controlled blasting using linear seed wave superposition modeling was required and implemented to reduce the far-field affects to the wall. This paper covers the work done by the drill and blast engineering group, controls used to protect the mine infrastructure, and the continuation of work-to-date of frequency controlled blasting for wall stability. The narrow width of the layback required the combination of hole sizes to blast large diameter production patterns with smaller diameter trim patterns in the same blast. A single blast had to use different burden & spacing and hole diameters and required the use of different timings throughout the pattern. Electronic detonators were required to limit blast vibrations and accommodate the specific timings needed to reduce low frequencies. The geotechnical group with the help of geotechnical radars worked with the drill and blast group on creating a tracking and reporting of blast performance. The radar readings informed the drill and blast engineers of the performance of the blast as it related to the long term performance of the highwall

Jan 1, 2019

By L. A. Heim, E. A. McCullough, N. J. Amiotte

The explosives industry is subject to the laws of multiple jurisdictions, which means that several regulatory agencies are responsible for governing different aspects of the commercial explosives industry. Among these regulators are the Mine Safety and Health Administration (MSHA) who implements codes that better ensure both occupational and public safety which is influenced by professional blasting projects and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), who enforces commercial explosives storage and security, among other responsibilities.

Jan 1, 2014

By Roger E. Scholl

Data on off-site low-rise building damage from underground nuclear testing at the Nevada Test Site (NTS) of the United States Atomic Energy Commission (AEC) [The AEC has been called the United States Energy Research ant Development Administration (ERDA) since 1975, but because the data presented here were gathered between 1966 and 1970, the AEC rather than ERDA is referred to in this paper.] are available for seven large tests in the period from 1966 to 1970. The data, while sparse, provide an adequate sample for the investigation of motion-damage relationships. Damage in the study is statistically described in terms of the incidence of damage complaints, the incidence of buildings damaged, and damage cost. Using 5%damped response spectrum acceleration amplitude to characterize ground motion, the plotted data fit reasonably well with previous motion-damage relationships established from extensive data available from the 1969 RULISON underground nuclear explosion (UNE) experiment conducted in western Colorado.

Jan 1, 1976

By Charles E. Joachim

Railroad and blast induced vibrations were measured in the vicinity of the proposed Big Bend Cutoff. Peak horizontal and vertical particle velocity relations were developed using least squares regression analysis. The dominant frequencies of these data are in the range of 30 to 50 hz. Therefore, allowable charge weight per 30 msec delay curves were generated for buildings (2 in./sec) and unlined tunnels (8 in./sec). A blasting contour map is presented for this site.

Jan 1, 1984

By Clive-Workman Davies, K K. Kabongo, Mensah Frimpong

Given the capital intensity of the dragline operation coupled with rising cost of explosives, the onus is on mine operators to make maximum use of explosives in blasting to assist dragline diggability. At a surface coal mine in South Africa large boulders necessitating secondary breakage and in some cases completely unfragmented sections of a blast resulting in low dragline diggability were encountered in the interburden blast. Twelve blasts were therefore closely monitored and dragline productivity evaluated. The ultimate aim was to improve the overall blasting performance and hence increase dragline productivity. Three areas were in focus; fragmentation assessment, dragline productivity assessment and cost analysis. The studies indicated unsatisfactory explosive and initiation performance, problematic blast design and questionable operators performance. It is established that dragline cost account for 60% of the total mining cost whereas the drilling and blasting cost account for the remaining 40% and that improvement in dragline productivity results in automatic cost saving.

Jan 1, 1996

By Calvin J. Konya

Many controversies and differences of opinion exist in blasting technology. The primer location in small diameter dynamite columns is an example of one of these controversial areas. It is generally agreed that in rotation firing of small diameter blastholes, primer placement near the bottom of the borehole is beneficial since it reduces the likelihood of cutoffs. The controversy results in the actual location of the primer in the bottom of the blasthole. Some references indicate that the primer cartridge should be the first cartridge in the bottom of the hole, with the cap pointed toward the collar of the hole. Others indicate that performance is improved with no sacrifice in safety by placing a tamped cartridge first in the hole, and the second cartridge being the primer. The following investigation provides some factual data for consideration.

Jan 1, 1980

By Paul McAnuff, Alastair Grogan

In Canada, the only vibration regulations which apply across the entire country are intended to protect fish spawning areas. The Provinces and Territories regulate mines and quarries, and are responsible for setting vibration and airblast regulations. Some Provinces have set specific regulations, while others leave these restrictions to the mines inspectors who can set limits on a case by case basis. For the most part, it is left to individual municipalities to regulate blast vibrations and airblast from other blasting activities, which differ from jurisdiction to jurisdiction, and in some cases are not enforced. Blasters working in different jurisdictions have to be aware of the applicable regulations for the area they are working.

Jan 1, 2005

By Corry Goumans

Photos 1 - 4 – Chris Elliott is a rock slope supervisor on a construction project east of Seattle, Washington. His job is to look after a “two man” scaling crew working on the rock bluffs some 300 feet in height along the I-90 interstate just east of the town Hyak. The Washington State Rock Engineers noticed a very large mass of unstable rock along the upper rock face and asked us to take it out. Chris is loading explosives in 1½" ” holes that are 8 to 10 feet deep by 40 feet long with 1¼” x 8” power primer on the unstable rock mass that is about 300 feet above the new road construction. I-90 runs east and west longside the new construction note the containment fence and the ship containers along the highway for protection and Lake Keechelus in the background.

Jan 1, 2014

By Callie Covert

This paper describes the application and results of a more efficient method of breaking boulders using dynamite and water. This method is being used for the disposal of boulders that result from pinnacle and cap rock remaining after blasting on highways and job sites. This method is a faster and less expensive use of dynamite to reduce oversized boulders than the conventional rock hammer. The problem with excessive fly rock has been substantially reduced when using this technique over traditional methods.

Jan 1, 2001

By Ruilin Yang

Based on large amounts of field data, this paper evaluates the validity of the above equations. During the evaluation, the different selections of the frequency in the equations were examined with field data. It is found that when they are used to estimate the vector sum values the above equations could result in large deviations from the values obtained directly from the field measurements or the waveform integration. The simple equations may be used to make rough estimations for single components of blast vibration provided that appropriate safety factors are taken into account. For single component vibration, the principal frequency (from ‘zero-crossing’) seems more effective to describe the blast vibration than the dominant frequency (fron FFT) for vibration peak value estimation using the simple equations.

Jan 1, 2012

By Trevor Garbutt, Peter Bellairs, Jason Sander, Glenn Shaw

The Yarrie Iron Ore mine is located in the Pilbara region of Western Australia some 200km eastsoutheast of Port Hedland, the closest large regional centre. The mine is owned by BHPIO who has contracted a large Australian mining contractor Roche Bros to be responsible for the total mining, crushing and trainloading functions. This paper describes a drill and blast optimisation program, resulting from the introduction of a new emulsion matrix called Titan@ Red used to manufacture both HANFO and pumped emulsion ANFO blends.

Jan 1, 1999

By John Wright

During June and July 1999 a United States Antarctic Program (USAP) team of three commercial divers and one blaster successMy removed an underwater rock obstruction which interfered with safe docking practices of research vessels that call at Palmer Station - the USAP research facility located on Anvers Island, Palmer Peninsula Area, Antarctica. Ordinarily, such a project might be considered routine. However, certain aspects of the project, particularly those dealing with logistics in a remote corner of the earth, sat3eguards for marine biota, and working underwater in the dark of the austral winter, conspired to make this project interesting. Even more challenging was ensuring the protection of the existing pier - a deeply corroded sheet pile structure backfilled with loose gravel and rock - which lay less than 50 feet away from the target obstruction, not to mention uncertainties at the outset as to the nature of the rock mass forming that obstruction.

Jan 1, 2001

By Thomas A. Gelormino, Ulrich La Fosse

"Deep blasting was used to densify foundation soils for a large manufacturing facility inChicopee,Massachusetts. A 360,000 square foot building, whose construction began inthe summer of 1990, is founded on alluvial deposits up to 90 feet in depth. These deposits are comprised of saturated very loose to loose fine to medium grained sands with traces of silt and gravel. During the building foundation design it was found that to withstand earthquake forces without soil liquefaction, it would be necessary to improve portions of the alluvial deposits by densification. The zone in need of densification extended from approximate depths of 20 to 50 feet. Several conventional densification methods, including vibrocompaction and deep dynamic compaction, were evaluated along with deep blasting. Detonation of 1-3/4 inch diameter charges of 65 percent gelatin dynamite (Atlas Power Primer) installed inside 2-inch diameter PVC casings to a depth of up to 40 feet, was used to achieve the desired densification. This method was selected over others due to its lower cost and decreased construction time. Although used in New England once in1940 for a dam and once in 1960 for a transmission line tower to improve foundation soils, there is no precedent found in the literature for densification by blasting to improve liquefiable soils below a proposed building. Details of a test program and the production blasting, including vibration data are presented. Pre-and post-blasting data conclusely shows an increase in the density of the sand deposit after blasting."

Jan 1, 1991