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By Jin Jingzhi, Wang Xuguang, Guan Li, Li Jianjin

Emulsion explosives are gaining a wider and wider commercial market and are displacing other composite slurry technologies. However, the grease-like state and essential thermodynamic instability of emulsion explosives cause inconvenience in production, transportation, storage and use and lead to gradual changes in performance. Emulsion powder explosives are designed to avoid these disadvantages. The formulation, process and properties of emulsion powder explosives made through a spin flash technology are described in this paper.

Jan 1, 1997

By J S. Brower

Disposing of the AMDP-1, Jackup drilling rig in the Arabian Gulf.

Jan 1, 1978

By William B. Lee, James J. Jurmu

The Cleveland-Cliffs Iron Company operates three open pit iron mines on the Marquette Iron Range of Michigan's Upper Peninsula. Open pit iron ore mining began in the area in the 1840's. Underground mining was predominant from 1860 through 1960. Large scale low grade-open pit iron ore mining began in the early 1950's with the establishment of the Humboldt Mine, concentrator and pelletizing plant. This pit operated until 1970, when the reserves were exhausted.

Jan 1, 1986

By R Fox, R Watt

On behalf of ICI's group of explosives companies around the world, a research programme is being undertaken to develop a new electrical shotfiring system which will have markedly improved safety features and operational advantages over existing initiating systems. The paper describes the development of the 'Magnadet' Electric Detonator and 'Magna' Primer and the field experience to date. It also indicates those areas where further work is being carried out on modification of the basic designs to meet specific application requirements.

Jan 1, 1981

By Bill Runner, James T. Ludwiczak

During the last few years, there has been a flood of local, state, and Federal government regulations concerning blasting. Many of the laws and regulations were written by individuals who know little about explosives, the purpose of blasting, or blasting vibration and damage. I feel that the special interest groups responsible for some of these regulations are not trying to regulate blasting, but to stop it completely by unreasonable, non-flexible, regulations. The most recent being the Office of Surface Mining regulations that are already spreading to the quarry industry and will, no doubt, spread to all blasting involving disturbance of the surface.

Jan 1, 1979

By R W. Givens

Comparison tests were performed on 6 emulsion concentrates, 3 microballoon sensitized emulsion concentrates, and 2 water gel concentrates from 8 different sources with ANFO used as a control standard. Variables measured include density, detonation, velocity, detonation pressure, calculated borehole pressure, viscosity, and lead cylinder deformation for blends of 15%, 30%, and 45% concentrate and AN/ANFO blends. Comparative results are presented for detonation velocity vs. deformation, and percentage of inherent air vs. deformation for these blends. It was hoped that these tests would serve as a tool to facilitate the comparison of different manufacturer's concentrates in AN/ANFO blends for equivalent performance characteristics and to help evaluate these products on an equal basis for bid solicitation purposes.

Jan 1, 1990

By Winston Wilches B., Scott Scovira

This paper discusses recent changes to the emulsion blend blasting agent used at the Drummond Pribbenow Mine in Colombia, one of the world’s largest open pit coal mines, and the resulting improvements in rock breakage and excavator productivity. Based on field evaluations, the use of High Density Ammonium Nitrate (HDAN) can be effectively implemented in an emulsion blend blasting agent, yielding excellent results in terms of energy release, shelf life and velocity of detonation (VOD). Field evaluations showed that formulations using HDAN exceed the performance of the actual 50%/50% emulsion/ANFO blend using Porous Prill Ammonium Nitrate (PPAN). PPAN is conventionally used for emulsion blend manufacturing, with physical characteristics to facilitate sensitivity during the detonation process.

Jan 1, 2014

By Alain Blanchier

Because in Europe and in many other countries as well every new project (quarry, mine, public work) needs a risk estimation to prove its feasibility, a model to estimate flyrock risks became necessary. This paper presents the basic hypothesis which should underlay such a model to estimate statistical flyrocks range for not only some single blasts but a whole project and in particular the way to take into account rockmass or blast pattern parameters variability. It describes a first usable quantitative flyrock model based on the characteristics of the blasting plan and of the generic laws utilised in casting and selective blasting operations and on a statistical approach of rockmass. In a second step, this paper discuss an approach of risks estimation compared to the classical one used in pyrotechnics studies for explosive magazine risks assessment.

Jan 1, 2013

By Dwayne Tannant, Jeffrey Loeb

Blasting techniques and protective measures exist that can mitigate risks associated with flyrock and the nuisance of vibration, and overpressure. However, these are often misused or not used because there are no prescriptive regulatory requirements and typically urban blasting guidelines do not exist. The relationship between the increasingly negative publicity that the urban blasting industry receives and the existing state of regulatory control on blasting in urban environments is presented.

Jan 1, 2012

By Gimtong Teowee

SDI has launched the Electronic Detonator Blasting System containing a set of robust serial protocol and hardware exhibiting great ease in field usability and deployment. Programmable delay time with increments of 1 ms up to 10s is possible with excellent timing accuracy. Bus length of up to 2 km containing 1600 EIMs can be employed. A key feature of the SDI Electronic Blasting System has been its high tolerance towards current leakage in the bus line.

Jan 1, 2007

By Robert Hopler

In part one we discussed a Chinese seismoscope allegedly invented and used in the year 136 (or 132, depending on the source). Interestingly, historical references to the measurement of earth movements then seem to be nonexistent until up into the 1700’s. There could be two explanations for this hiatus: first, that there were no earthquakes in the world for 1600 years, or, second, the “Dark Ages” really did exist, where intellectual inquiry and all sorts of learning came to a halt. Of course there were earthquakes, so the explanation for the lack of a record of invention is the reality of the Dark Ages. explained is the fact that the Dark Ages ended in about A.D. 1000, but that is beyond the scope of this story.

Jan 1, 2006

There is an intuitive tendency to equate rock strength with rock stability, yet the two must be evaluated separately. A slope in strong hard rock is not necessarily stable, nor is a slope in weathered weak rock necessarily unstable. In some cases the reverse is true, depending on the geometry of joints and weak planes. The time element is a matter of special concern, that is how suddenly the failure begins and how rapidly it progresses. Sudden failures can be catastrophic, whereas creep usually is not. In soils and weathered rock, the process is usually incremental and is more likely to give some warning of impending failure. With careful observation, the failure process in these materials can be detected and monitored instrumentally or visually. In some cases, the slope may be stabilized, reinforced or modified. When that is not possible, there is usually enough time on this type of slope to remove men and equipment from the area before complete failure occurs.

Jan 1, 1996

By Kenneth Medearis

The accurate prediction of possible damage to historic structures subjected to blasting-related ground motions is not infrequently the dominant factor in whether or not a mining or quarrying operation is allowed to proceed. A recent scenario involving an 1802 Pennsylvania Historic House was resolved satisfactorily, primarily because of the use of modern structural dynamics analysis techniques rather than simplistic peak particle velocity guidelines. One of the associated dominating factors was the truly significant agreement of the analysis results and the values obtained from actual on-site test shot blast motion recordings.

Jan 1, 1993

By Courtney Vallejo, Rafiqul Tarefder

This study examines the effects of small scale airblast experiments on cohesive soils and the resulting ground vibrations and crater geometries. Relationships for ground vibration attenuation with soil depth and distance from the blast source were developed. The study is part of a broader research topic of understanding the vulnerability of earthen embankment dams to blast loading. Many earthen embankment dams in the United States were constructed more than fifty years ago and were not designed to withstand high-stress loading such as blast loading. These structures may be susceptible to failure and it is important to describe the response of the earthen dam during a blast event.

Jan 1, 2013

By Sergio Segovia Parra, Victor Hernan Sheen Uriol

This contribution of the concept of mass blasting both closing and production allows breaking paradigms, to limit the number of tons to thunder. The areas of geotechnical different mining large mining companies worldwide and especially from the National Copper Corporation (CODELCO, Chile) has been declining volumes closing blasting and production, with the misconception to protect the end walls of the pit, before any geotechnical risks caused by various types of faults; especially the circular faults. A blasting of small tonnage can do more damage to a wall when it is not properly sequenced, leading to the coupling of the wave train and therefore the exponential damage in/s (peak particle velocity, PPV) on the wall of the Tagus. Blasting closing mass production and contribute technically and operationally in the dynamics of the following operations: loading, hauling, crushing, processing and preparation of the final product; eliminating delays to return to thunder small volumes where one must stop all mine equipment, incurring high costs and especially losing valuable time in the continuity of the following unit activities.

Jan 1, 2015

By Robin L. Simmons

Mining in the Genesis open pit has been conducted above the active haulage and ventilation declines of the Deep Star underground mine. Production has continued in both mines. The Deep Star haulage and ventilation declines, the primary and secondary egresses respectively, had to remain open and safe for travel until the new haulage and ventilation accesses were completed. Eventually, the upper 350 feet in each decline will be removed. The declines are in relatively competent calc-silicate hornfels with several high-angle, northeast-striking, clay-filled or open-spaced fault zones that create localized areas of poor ground requiring steel sets. To maintain the integrity of the declines, blast-induced vibration levels and damage were monitored in both declines after each surface blast. Seven geophones were installed in the declines to monitor peak particle velocity and peak vibration frequency. These data helped design subsequent blasts and predict expected vibration and damage levels. Blast design modifications included reducing the pattern size, reducing the powder factor and limiting blasthole detonations per delay. While limiting blast-induced vibration, these blast design modifications had to allow effective surface mining to continue. Linear regression analysis of peak particle velocity and scaled distance was used to determine the scaled distance necessary to keep the peak particle velocity under 2 inches per second. To date, the new ventilation raise, which is also the secondary escapeway, has been established and safe conditions were maintained in the original ventilation decline. Data collection and conscientious blasting procedures continue above the haulage decline.

Jan 1, 1998

By Ali Kahriman

This paper presents the results of ground vibration and air blast measurements from tunnel blasting activities during the construction of the Beylerbeyi-Kucuksu waste water tunnel under a residential area in Istanbul, Turkey. Within the scope of the study, the blasting pattern of the tunnel was engineered using Tunnel2000 design software and field studies and measurements for evaluating the productivity and safety of shots were realized for 136 rounds. During the study, the advance of the tunnel, face condition, ground vibration, air blast and neighbours’ complains and comments after every round were observed and the tunnel pattern was improved. Finally, an empirical relation for this tunnel route was developed between scaled distance and maximum amount of explosives, to continue activities in a safe and productive manner.

Jan 1, 2006

By Diane F. Baker, Cathy Aimone-Martin

A series of small-scale explosive experiments were conducted in a perlite mine near Socorro, New Mexico. These experiments were a joint effort between Los Alamos National Laboratory, New Mexico Institute Of Mining and Technology, Southern Methodist University, and Defense Nuclear Agency. The purpose of these tests was to measure the changes in the shock wave and seismic coupling as a function of depth of burial and structural setting. The size of the explosive charges ranged from 1 to 68 kg. Over 1150 measurements of velocity and acceleration were made on thirteen experiments using three component sensors. The sensors were placed to maximize the azimuthal coverage as well as to provide data at a variety of ranges from ~1 to 130 m A few far field measurements were made at ranges of ~2Êkm. While the bulk of the measurements were made on the surface, high g accelerometers were placed in one instrumentation borehole to provide some free-field measurements. Preliminary results indicate that significant differences in the amplitudes of signals can occur when the location of the explosive charges are changed by only meters. Part of the observed difference is attributed to variations in the rock immediately adjacent to the charge affecting the shock coupling; and part to the effects of the site characteristics.

Jan 1, 1994

By Quian Liu

Since the establishment of the CANMET Experimental Mine in Val d'Or, Quebec in 1991, research activities in rock fragmentation have been carried out not only in the underground laboratory but also in production mines in the north-west Quebec region. Among the instruments available for rock fragmentation, the Kodak EktaPro 1000 Motion Analyzer (also called the high speed video system) has been one of the most useful tools for monitoring blasts in both underground and open pit. This system is capable of recording events at rates from 50 to 12,000 frames per second (fps). The buffer memory has a capacity of storing 2050 images. To use this system in the underground, a steel box was made with a bullet-proof glass in the front to protect the camera. The processing and recording equipment are placed in an aluminum case which can be located about 30 m away from the camera via an extension cable. For each blast monitored, high frequency geophones and accelerometers were used to monitor ground vibrations and give a timing reference of the explosive detonations to correlate with the observation of the captured images.

Jan 1, 1994

By Robert B. Hopler

The Hercudet ? Nonelectric Delay Blasting Cap System has undergone significant changes since the last paper on the subject was presented at the 1978 S.E.E. Conference. The changes have been made to improve reliability of the blasting machine at low temperatures, and to improve efficiency and economy in usage in surface mining. The paper includes examples of the blast design process, details of use of the new in-hole connected cap, and delay patterns which have found use in quarrying and coal stripping.

Jan 1, 1980