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By Raden Haris Handayana, Jihan Farhan Lubis, Milia Putri, Tengku Deli Hamonangan Hasibuan, Sani Salahudin

An environmental issue that must be controlled from coal overburden blasting near the structure is ground vibration. Damaging ground vibration is the effect exerted from residual energy from blasting that does not work to fracture the rocks. Sebuku Tanjung Coal is a coal mining that operates T3 Pit adjacent to the High Voltage Tower. This structure is included in the Class 5 building with a maximum Peak Particle Velocity (PPV) of 40 mm/s. The shortest distance from the blasting location to the structure is 105 m. The initiation system used is electronic detonators combinate with emulsion as an explosives type. In Indonesia, the government regulated vibration limitation on SNI 7571:2010. The blast outcomes targeted are PPV below 40 mm/s, fragmentation size <80 cm for Excavator Komatsu PC-2000, and digging time <12 seconds. In this paper, the blast design was engineered by conducting Signature Hole Analysis for optimizing delay timing configuration and Scale Distance regression analysis to determine optimum charge weight per delay at the blast site. PPV results from 30 blastings achieved 100% below 40 mm/s with the range of about 1.773-30.250 mm/s. The deviation between PPV prediction to PPV actual is less than ±18% which provides the blasting with electronic detonator resulting in good PPV prediction for controlling vibration. The average fragmentation size (D80) is 55.81 cm in the 1st layer and 54.81 cm in the 2nd layer. The average digging time is 10.30 seconds in the 1st layer and 10.12 seconds in the 2nd layer.

Feb 6, 2023

By G. Gomez Ciments-Calcia

The sources of complaints by neighbours of the operating quarry are due to the 3 following causes : - Impulsional noises or air hoch wawes – Vibrations - D u s t How a blasting in a quarry operation is felt by neighbours cannot be measured solely by the various limits set by national and European regulations regarding vibrations and air shock waves (sound pressure).

Jan 1, 2002

By Ralph Dawson

The following additions to SLP-4 “ALWAYS AND NEVERS” have been approved by the Board of Governors since the last printing 6/97 and will be included in the next printing soon. They are also included in the Second Printing of the 17th Edition of the ISEE Blasters Handbook. Review them and apply those which might be applicable into your blasting program now.

Jan 1, 2001

By Attie J. Goosen, William L. Spiteri

Although the physical characteristics of ANFO made from porous prilled ammonium nitrate (PPAN) have been altered by the addition of crystal modifiers, the optimisation of prilling processes and the admixture of waterproofing agents, the sensitivity of this explosive has not been modified on a commercial scale in the 40 years since its accidental discovery.

Jan 1, 1995

By Tapan Goswami

The expectation from the blasting engineers and shotfirers is often that explosives will perform optimally at all times. However, in reality, non-ideal situations exist on mine sites and occurrences of poor explosives performance are common. Often the cause is difficult to identify. Having a good application technique and analysis skills will minimise the risk of poor performance. This paper will discuss the experiences gained by the author while blasting in the Hunter Valley, Australia.

Jan 1, 2003

By James A. McGrath

"The predominant key word associated with all commercial blasting methods is “safety”. Safetyshould take precedent over all other aspects of the entire explosives industry which on a wholehas had an excellent track record as to number of injuries per unit of hours worked at all blastsites throughout our country."

Jan 1, 1999

By Randy Wheeler

One of the more difficult topics to address concerns the effects of vibration on historic structures. Not only blast induced vibration, but also vibration from other transient and semi-continuous sources like, traffic, human activity, and environment forces. A common question might be, “What level of blast-re l a ted PPV is considered safe?” A review of some of the papers available from the ISEE Explosives Reference Database on CD ROM shows that 0.50 inch per second was often used. It was not clear on what basis this value was selected except that it represents the low frequency limit for plaster developed by the United States Bureau of Mines in RI 8507. In another case, a limit of 0.20 inch per second was mentioned, apparently simply because it was ten times less than 2.00 inches per second.

Jan 1, 2004

By Chris Breeds, Larry Leone, Jerry Wallace

Project Owners typically require General and Detailed Blast Plans when blasting close to important structures and specify the maximum allowable peak particle velocity for each potentially affected structure. Low, residential level PPV limits may be specified which significantly restricts the potential for blasting to be effectively used. Contractor’s responding to these contract conditions typically cite historic case studies which may, or may not, apply to the specific situation and/or types of structures for which limits have been set. A long submittal cycle typically follows.

Jan 1, 2010

By Jack Eloranta

The winning of metals often requires fine grinding of very hard ore. The US Bureau of mines measured compressive strengths exceeding 100,000 PSI (700 MPa) in Minnesota taconites. Grinding down to 300 mesh (50 µ) is required for some fine-grained taconites. While other metal ores may not be as strong, significant grinding costs are the rule rather than the exception. One author recently reported that a 7% drop in grinding costs would fully offset a doubling of the drill and blast budget. Another author found that drill and blast costs were 13% of the costs of producing iron ore concentrate while fine crushing and grinding were over 60% of the cost of producing concentrate.

Jan 1, 2013

By Gerald W. Longenecker

For decades, traditional hydraulic engineering approaches have been used for sizing stream channels when stream relocation efforts have been necessary to allow for the advancement of quarry and other surface mining operations. These approaches have been based on various ydraulic models to design channel cross sections and slopes that could pass the required regulatory design storm such as the 2-, 5, lo-, 25-, 50-, or even loo-year events. Designing the stream channel to handle these more extreme ,storm events would often lead to large channel designs which required extensive bank and channel bottom stabilization techniques including concrete, rip rap, gabions, or other expensive approaches. The constructed channels often required ongoing maintenance to remove accumulated sediment and other debris which would settle out and reduce the hydraulic capacity of the channel.

Jan 1, 1998

By P D. Katsabanis

This chapter describes the principles for the derivation of the equations for a detonation wave. The importance of the equation of state for the detonation products is demonstrated and commonly used equations of state are discussed. Furthermore a brief introduction to the TIGER code is presented.

Jan 1, 1991

By Michael S. Wieland

This report focuses on the U.S. Bureau of Mines research regarding desensitization and malfunction of delay detonators and cap-sensitive explosives. Delay blasting in underground coal generates tremendous shock waves and rifting forces that fracture and heave coal. The shock waves from charge explosions radiate outward in all directions through the coal, impacting neighboring charges with later delays. The impact phenomena have debilitating effects, causing degrees of reduced charge performance ranging from misfires or weak detonations to out-of-sequence detonations. Impaired charges react poorly, fracture less coal, and produce fumes with higher toxicity. Coal-mine, underwater, and simulator tests were conducted to more thoroughly understand the shock damage mechanism. Recently the U.S. Bureau of Mines partially resolved the malfunction problem by demonstrating the feasibility of formulating a rugged explosive. This rugged cap-sensitive candidate passed the requisite tests for certifying an underground coal-mine explosive. With natural aging the formulation rapidly lost initiation sensitivity. The charge formulation had to be rebatched to finish the testing and therefore could not be certified.

Jan 1, 1992

By Takuya Taguchi, Toshihiro Ogata, Atsuio Inoue, Shigeyuki Sasaki

Highly improved drilling machines and mucking machines have been used for the underground construction. To have rapid construction, the roles of blasting operation ha ve been growing more important. At the most tunneling of present, cartridged emulsion explosives have been used for a blasting in Japan. Under this circumstance, a blasting system of ANFO explosives using loading machine has been used recently for a tunnel blasting. However, ANFO has some problems, such as a useless explosives in wet boreholes, bad blasting fumes and the ammonia gas due to the decomposition of ammonium nitrate in contact with the sprayed concrete in tunnel.

Jan 1, 2005

By Norman Disley, David B. Counter, Lionel Hebert

Misfires in underground and surface production blasts can be costly. Costs can arise from loss of resource, production interruptions, having to redrill or otherwise refire the blast (a hazardous process at best), due to added secondary blasting or breakage, and/or from increased LHD maintenance costs attributable to poor fragmentation.

Jan 1, 1996

By Lawrence W. Gubbe

Air blast associated with detonation of explosives in mining, construction or military applications is often responsible for complaints by people who live or work in the vicinity of the activity. Most often, the complaints are based on the perception that vibration caused by the airblast damaged one or more residential buildings that may be located within several hundred feet or several miles from the blast site. The potential for airblast to cause damage is related to the amplitude and frequency of the airblast overpressure wave at the receptor. Amplitude and frequency of the overpressure wave are, in turn, dependent upon the type and amount of explosive detonated; the degree of confinement; the distance the wave travels; the topography between the blast site and the receptor; and, atmospheric conditions. It is well known that, as the result of atmospheric focusing, the amplitude of airblast overpressure that exists relatively far from the blast site may be substantially higher than the amplitude associated with the attenuated wave in an isotropic atmosphere. Two methods are available to predict baseline overpressures 1) the Sandia Laboratories, Atomic Energy Commission method as extended by the Naval Ordinance Laboratory (NOL method) and the Ballistic Research Laboratory method (BRL method). These methods are developed by different techniques, are based on different idealized atmospheres and predict widely different results. The amplification factor applied to account for the effect of focusing must be consistent with the method used to predict the baseline overpressure. Theoretically, the amplitude of the overpressure at distances several miles from the blast site could be more than 25 to 100 times the amplitude of the attenuated wave predicted by the BRL method. However, based on comparisons with measured overpressure data is probably less than approximately 3 times the amplitude of the attenuated wave as predicted by the NOL method. This paper is based on research conducted as part of investigations of airblast damage complaints associated with an accidental explosion near Eveleth, Minnesota and with the disposal of military explosives by detonation at the Sierra Army Depot near Herlong, California. The techniques available for estimating the airblast overpressure that might be generated at various distances from the blast site and criteria for evaluating the potential for damage are examined.

Jan 1, 2004

By Alastair C. Torrance

"A brief review of the Australian mining industry is given followed by a more detailed treatment of a study of the influence of primer Size on explosive performance. This is based on a joint research programme conducted by BHP Central Research Laboratories and Dyno Wesfarmers Ltd and examined the effect of the size of cast primers on the run up and steady state detonation velocitiesof ammonium nitrate based explosives as a function of blasthole diameter. The field trials examined a numter of the Dynamo 'Westfarmers HDF series of primers in conjunction with ANFO, emulsion and watergel explosives. Results indicate that the iun up velocity of 187 mm diameter ANFO charges is negligible using cast primers as small as 150g. However, emulsion and watergel explosives did exhibit run up in both 187 and 3:1mm diameter blastholes, independent of the size of primer. This could last from 7 to 10 blashole diameters"

Jan 1, 1991

By Reinhold Schnell, Piers Wendlandt, Nathan Rouse

Drilling and blasting are key components of every hard-rock (i.e.,metal/nonmetal/coal) mining operation. Well-executed and maintained drilling and blasting can have a major positive impact on the overall success of such operations. This case study presents the implementation of a new drill and blast engineer position and systematic improvement of the drill and blast operations at a surface metal mine. The findings of and lessons learned from this case study can be applied toother mine operations to improve safety, production, efficiency, and cost savings. Focus areas for the project included refined communications, operational practices and procedures, planning, designing, and data collection and analysis. This case study showed improved efficiency in communication and planning among the engineers, operations team, and contractor groups over the course of the project. An increased awareness of long-term plans and needs for the drills and blasters reduced or eliminated existing delays. Test blasts that implemented new drill and blast designs and updated operational practices and procedures were tested to streamline the process. Constraints regarding explosive product shipments, geological considerations, and a uniform powder factor provided the basis for new blast designs.

By Christian J. Sorensen, Christopher Armstrong, Andrew Matejunas

A team consisting of junior and senior mechanical engineering students at New Mexico Tech worked on the design of an explosively loaded vessel, with a maximum load of 15 grams (0.53 oz) TNT equivalent explosive. The main challenge presented was to meet the stringent sample positioning specification of 3 microns in two Degrees Of Freedom (DOF) and one degree of rotation in a third DOF. This is to accommodate precise sample placement in a tight x-ray beam, and to bring areas such as explosives/metal interfaces into magnified field-of-view photography. This presentation describes the process and design decisions to arrive at the final product presented to LANL in December 2014. Our engineering analysis techniques will be reviewed, including use of American Society of Mechanical Engineers (ASME) Boiling & Pressure Vessel Code (BPVC) Code Case for Impulse Loaded Pressure Vessels (ASME BPVC Code Case 2564-3). Also discussed will be integration of Hydrocode computer models with Finite Element Method analysis.

Jan 1, 2015

By R. Bitmead, R Barker, A. Drake

The opencut coal mine is located about 50 km west of Brisbane, the capital city of Queensland in Australia and produces about 140 000 tonnes per annum of high grade steaming coal utilising a small team (ten) of personnel to mine remnants of the Aberdare and Bluff seams left by previous underground mining. This, in itself, is not remarkable except that one of the seams has commenced spontaneously cornbusting resulting in temperatures in excess of 55’C commonly being encountered with portions of the p’it being wreathed in steam. To extend mine life, the mine required a blasting system that would: . Safely blast in temperatures below 100°C . Significantly reduce overall unit costs . Not increase the current vibration impacts on nearby housing . Not increase flyrock.

Jan 1, 2002

By Brad Bulow

Blasting is an essentially violent process aimed to disrupt and loosen rock for productive excavation. Some dilution of any ore present is the inevitable result. This makes blasting a dirty word to most geologists, particularly in narrow vein gold mines. A 1% increase in gold recovery may be worth $1 M extra revenue to a large mine.

Jan 1, 2000