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Since the ecrly 1970's several factcrs have changed. In the East the larger tracts of coal mined with large eauipment are being dePleted, The cost of moving the larger equipment from small tract to small tract becomes eccnomicallv unattractive, Conseauently, the tracts are being mined with smal!er draglines or with loader/truck haulage combination, This has resulted in a major increase in the cost of moving a cubic yard of overburden,

Jan 1, 1989

By Mark A. Williams

Topography and geology greatly impact the decision of how to plan and operate a surface mine. To extract coal, five primary surface mrning methods are practiced in the United States. These include contour strip. mountamtop removal, area, modified area, and open pit mining methods. The first four approaches are commonly associated with coal mining while open pit techniques, although used in the mining of coal, are more commonly applied to the mining of hard rock, metals, and aggregates. Various sub-routines of the primary surface mining methods are likewrse applied rn the industry.

Jan 1, 1991

By Frank Sames

Most Blasting Programs are developed focussing on the environmental impact with respect to blast vibration and airblast. Compliance with existing regulations or policies limiting the immissions are generally achieved through constrains in the blast design, or monitoring programs. Efficient monitoring programs combine compliance monitoring and blast assessment. Signals, which are obtained in the area of direct influence of the seismic source, can contain valuable information about the blast design parameters. Techniques to analyze blast vibration signals have advanced and can assist in understanding the contribution of individual blast parameters to blast vibration and airblast. Advanced signal analysis encompasses magnitude analysis, Fast Fourier Transforms (FFT) and frequency scans in the frequency domain, as well as filtering in the time domain. Through examples, the advanced signal analysis techniques and their limitations are described and discussed, showing the impact of blast timing, timing accuracy, charge configuration and the geology dependent transmission behavior. Optimization criteria and pragmatic monitoring programs can be developed on the basis of the most influential blast parameters. In addition, however, safety and the cost efficiency of the blasting program are essential to the success of an operation. That is where advanced signal analysis techniques can interface with blast planning, computer assisted modeling and information systems. A valuable process can be developed to ensure compliance with existing regulations and efficient risk management for mining operations, while tracking cost and supporting operational decisions. A conceptual blasting information system is presented.

Jan 1, 2000

By Thierry Bernard, Guy Gagnon

Blasting at very close proximity to urban areas is typically a situation where both local communities and mining stakeholders get nervous. The context becomes logically even more tensed when the blasting operations have to be performed above an old underground mine. When mitigating subsidence risks requires firing the largest possible shots, the nuisance control (flyrock, vibration, and noise) required by local and national regulations, contrarily urge for being more conservative.

Jan 1, 2014

By Anthony J. Konya, Calvin J. Konya

Mine sites and construction projects have faced problems with blasting a smooth back wall. This lead to safety concerns with slope stability and rock falls from the walls. Decades ago Dr. Calvin Konya began a special type of blasting called “Precision Presplitting”. This form of presplitting used relatively light loads based on the rock type being blasted. The explosive loads were estimated for each rock type and adjusted as blasting progressed. This current research project also determined a new equation for prediction of the ground vibration from one type of presplitting and compared it to vibration from production blasting.

Jan 1, 2016

By Ruilin Yang

"Blast vibrations are essentially a strain/stress wave propagating in rock or structures inthe vicinity of a blast. However, blast vibration has always been quantified in terms ofpeak particle velocity (PPV) or acceleration (PPA), and a meaningful relationshipbetween blast vibration and strain/stress has not been established. The determination ofthe dynamic strain from blast vibration may improve quantification of blast damage andselection of a blast vibration limit for critical structures or high walls. Dynamic strainrelates to rock mechanics or material strength more directly than peak particle velocity(PPV). This paper documents a method to calculate the three-dimensional dynamic straintensor from recorded blast vibration signals. The method is based on determination of thedisplacement gradient at a point of interest for each time instance during the vibrationduration. The method to calculate dynamic strain is applicable to generic seismicwaveforms including near and far field blast vibration from a production blast withmultiple blast holes. In order to minimize measurement errors the specifications of thespacing between monitors and the sampling frequency of the vibration recording aredescribed."

Jan 1, 2012

By H. Venkatesh, Balachander R.

This article discusses the method that was adopted for controlling damage to rock mass while excavating an underground powerhouse cavern at Tala Hydroelectric Project. It discusses in detail the near field vibration studies carried out and the safe vibration levels established for that rock mass condition.

Jan 1, 2006

By Francisco Sena Leite, Pedro Brito, Auã Kiahla, Raquel Carvalhinha, Tomi Kouvonen, Vinicius Miranda

Shockwaves that generate vibration in the surrounding environment of a blast, are one of the most important factors to control drill & blasting works near delicate buildings as well as in sensitive structures (wall control). On top of the damage to the buildings themselves, sensitive equipment such as computers, measurement apparatus and medical devices can be also compromised. The most commonly measured values from vibration are PPV (peak particle velocity), acceleration and displacement. Some devices and techniques have been developed in the last decades to measure the impacts of these vibratory phenomena. This information can be used to predict levels of vibration for future blasts and improve their quality of design using the attenuation law. From traditional studies to modern seismographs, a range of solutions are used for this propose. The main problem of applying this kind of technology is the high cost associated with each measurement device. In order to measure the ground vibration using new technologies while lowering the cost, a device has been developed using a microcontroller and electronic sensors commonly found on the market. This new equipment was tested side by side with traditional seismographs and the results were sent to a server for analysis. After several blasts, the necessary data was generated for the validation of the prototype. Through numerical mathematical processing (Taylor’s approach and numerical derivation) the original data supplied by the accelerometer’s sensors was transformed into velocity and, after the data mining, a statistics residue analysis was applied in order to evaluate if the data from the prototype and from the traditional seismographs were similar. The data from each system was used to estimate the attenuation law and the results are shown in this paper.

By Don W. Lake

Of all the blast monitor& instrumentation systems and techniques av&able today, highspeed photography and videography remain as the most valuable, stand alone, diagnostic techniques to evaluate full scale blasts in the mining and explosives industries. Highspeed image data, coupled with information from other instrumentation systems, such as continuous VOD records, seismographs, laser surveying systems, refraction seismographs, etc. can eIiminate many assumptions about what actually took place in a blast. Thus, diagnostic confidence in evaluating both good and bad blasts is increased, and optimum blast designs are achieved considerably faster when compared to the trial and error approach or relying on just the experience factor.

Jan 1, 1992

By Michael Mann, Kenneth K. Eltschlager

The International Society of Explosives Engineers (ISEE) Standards Committee has recently updated both the Field Practice Guidelines for Blasting Seismographs and the Performance Specifications for Blasting Seismographs. The revisions are the result of public and industry input along with recommendations of the ISEE Blast Vibration and Seismograph Section. The committee is comprised of blasting seismograph manufacturers, users and general interest personnel. On an as needed basis, subject matter experts are enlisted to advise the committee. Three phases of activities are necessary for each revision cycle: request for comment on the existing standard, first draft revision of the standard based on public input, and final draft approval by the ISEE Board of Directors. The ISEE standards revision process will be explained and each standard will be discussed along with the significant revisions from the latest revision cycle.

Jan 1, 2018

By Carl Lubbe, Ron Frye, Wayne Curtis, Julie Pecori, Dan Leach

Blasting conducted in the USA using the new Electronic Initiation System developed by Altech has shown that an accurate delay system will benefit the customer. Results from test work clearly showed that improved fragmentation was effected and blast vibration was at least similar to that currently found at the test venue with improvements possible.

Jan 1, 1997

By Laura Bastemante, Bruce Vandenberg, Fred Huettig

Recent advances in solid-state, field portable, fast framing video camera systems and PC based frame capture hardware now allow blast imaging up to loo0 frames per second. Up to 8 seconds of data can be stored directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the KineView 1256P system and compare these with the analogous aspects of film based cameras.

Jan 1, 1997

By Mark E. Hammele

A number of new thoughts have recently emerged concerning the role of air decks, stemming, gas confinement and gross motion in specific blasting environments and applications. Field research in full-scale production environments is based on the theoret ical work f i rst proposed at the Universi ty of Maryland’s Fracture Mechanics Laboratory.

Jan 1, 1989

By Unknown

More than 60 years ago Lakota (Sioux) Chief Henry Standing Bear asked Korczak Ziolkowski to create a monument of Crazy Horse in the sacred Black Hills. Today, you can see Standing Bear’s dream has grown into enormous reality. Crazy Horse Memorial, mankind’s largest mountain carving in progress, is being carved in the round and when completed will be 641 feet long and 563 feet high. Crazy Horse is only 17 miles from Mount Rushmore National Memorial, giving South Dakota unique boasting rights for having two extraordinary mountain carvings in such close proximity

Jan 1, 2009

By Christopher Jon Preston

This paper describes a type of ammonium nitrate (AN) produced in a patented experimental atomization/aerodynamic process. This AN exhibits outstanding properties for use as a main ingredient to a new family of AN-based commercial explosives. Micro-particle ammonium nitrate (MP-AN) is produced by atomizing either an 83% or 85% AN solution which has been doped with a two component surfactant NSol 1000 (NSol). NSol imparts some water-resistance as well as provides a means of increasing density and bulk strength. Increased detonation velocities, well in the range of emulsion explosives, can be achieved. The maximum manufacturing temperature is less than 100°C. The methodology has the potential of being environmentally friendly since any effluent can be recycled back into a make-up tank to be re-used by the closed loop method. The process has a small footprint.

Jan 1, 2015

By Douglas Rudenko

Have you ever had a neighbor complain about a blast one day, but says the next day’s blast was better, even though the Peak Particle Velocity (PPV) increased? How about neighbors that complain about a small trimming shot, but don’t complain about a big production shot? Have you ever reduced the pounds/delay and gotten more complaints? Mine operators are often bewildered when trying to correlate blast design parameters to homeowner complaints.

Jan 1, 2002

By Stanley Griff, William Herrera, William O. Seals

"The Navy initiated liquid propellant research in the early 1940's. The first promising Navy liquid propellant, Otto Fuel II, was developd in the early 1950 as a potential torpedo fuel. Later, the Navy developed a HAN based liquid propellant designated NOS-365, a hydroxylammonium nitrate, isopropylammonium nitrate and water formulation. A large gas volume generated by this propellant produced a large wake behind the torpedo. As one can readily understand, this negated the useof the propellant for this application. Recognizing the large gas volume as a desirable propulsion system for guns, the Navy embarked upon a gun propellant proqam. Utilizing a bulk loaded gun sysytem, the program failed when the gun was destroyed by the propellant detonating."

Jan 1, 1990

By Cathy Aimone-Martin, Brent Meins

A comprehensive instrumentation program was implemented at the Howland Hook Marine Terminal on Staten Island, NY during proximate underwater rock blasting in 2014. Forty-two blasts took place over a 4-week period to deepen the 1200-ft (366 m) Berth 3 from -45 ft (-14 m) to -50 ft (-15 m) MLW to accommodate Post-Panamax vessels. Approximately 86,000 yd3 (65,752 m3) were blasted 120 to 9 ft (37 to 2.7 m) from the wharf to a total depth of -57 ft (-17.4 m). Pre-blast planning included developing and implementing a comprehensive monitoring plan and setting vibration and strain limits to protect the wharf. The plan outlined methods to measure vibrations on five corners of four concrete deck sections, on five concrete-filled pipe piles just below the pile cap near deck corners, and in bedrock adjacent to pile sockets. Water overpressures were measured near instrumented piles for 19 blasts closest to the wharf. A total of 19 geophones were secured to the wharf structure and buried 12 ft (3.7 m) in drilled holes.

Jan 1, 2016

By Jackson R. Pressley, M L. Hopkins, R E. Danell, N T. Moxon, Andrew Bowman

Efficient and cost effective blasting is achieved by closely matching the explosive energy to the strength of the material in which it is being used. Although there are many empirical relationships wich approximate this situation complete the blast optimization can only be achieved by quantitatively assessing explosive/rock interactions and explosive performance. The performance of an explosive is essentially governed by its velocity of detonation or the rate at which the detonation wave travels through the explosive column.

Jan 1, 1991

By Alejandro Ferrada Vergara

Most blasting techniques that are designed to improve fragmentation and subsequently improve ore work index to downstream comminution processes, apply powder or energy factor increases, either by stretching the drilling pattern (burden/spacing ratio) implementing faster initiation sequences or using more energetic explosives. The new application will move detonation parameters up, making the blasting process riskier for the surrounding boreholes, explosive column or initiation systems functioning.

Jan 1, 2016