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By K Ramachandra Rao

Joints, fractures and other structural defects bring anisotropic character Into a rock mass. Conventional methods of blast design In a rock mass consisting phyllites, mica schist etc., which are characterised by the presence of closely spaced, nearly vertical planar Joints, result In formation of large slabs which cannot be handled by the excavation and loading equipment without resorting to secondary blasting. Frequent secondary blasting Is not only expensive but also, Is a source of environmental hazard. Interruption of production cycles frequently, leads to uneconomical mining. This problem could be minimised by designing blasts which produce forces whose components along and across the joints/fracture planes Is lust sufficient to break the rock mass In both directions. Rock mass strength can be assessed from field and Laboratory tests. Projecting structural features with respect to bench orientation on a stereoplot helps In assessing magnitude and direction of force vectors required to fragment the rock mass to the desired size range.

Jan 1, 1995

By Francisco Sena Leite, Thomas Palangio, Vinicius Miranda

With an increasing pressure to find efficiencies in the mining industry, operations are looking for continuous improvement tools to validate blasting procedures, a crucial and often overlooked area of the process. Using case studies completed at both small and large-scale mining operations, this technical paper proposes a practical methodology for pattern expansion studies, taking into account terrain parameters, rock quality and explosive strength. This technical paper will use a series of tools geared towards an economical continuous improvement procedure, using UAV particle size analysis to optimize blasting based on “generalized reduced gradient” for non-linear problems, with cost savings being the main objective. For the validation of this methodology, one scenario was created based on the operation’s budget: an economical continuous improvement plan that relied on manual data collection methods in order to baseline and optimize procedures.

Jan 1, 2018

By Jeff Wachendorf

As the title implies, this paper details the start of a cast blasting and the design flexibility required to satisfy different parameters encountered on a large coal mine employing cast blasting as the program has grown and evolved around the town of Colstrip, Montana. As strip ratios have increased, the need to adapt and find solutions to provide coal at a reasonable cost to the mine mouth power plants has risen. Colstrip, Montana has a long history of coal mining which dates back to the early 1920s when Foley Brothers began supplying coal strictly for powering locomotive engines.

Jan 1, 2015

By Anders Nordqvist

LKAB operates an underground iron ore mine in Malmberget in the northern part of Sweden. Twelve different orebodies are mined today using both longitudinal and transversal sublevel caving as mining method. The town of Malmberget is located close to the mining area. The need for urban transformation, moving people and houses, is evident for many reasons. The mining methods used have inherent subsidence issues and there are also vibrations from blasting and mine induced seismic events.

Jan 1, 2018

By Ruilin Lang

This paper presents an application of 3-D plots and non-linear regressions to define a sitespecific form of the charge weight scaled distance. The PPV (PPA) of single hole blasts is normally considered as a function of two independent variables - the charge weight and the distance. It is of great importance to obtain the relationship of the function accurately for a concerned site in terms of blast vibration analysis and modeling. However, in pre-computer time it was difficult to plot 3-D graphs. Consequently, a charge weight scaled distance was used to plot the PPV (or PPA) against the scaled distance as 2-D graphs. Blast vibration investigators use several forms of the charge weight scaled distances to plot data. We can exemplify them with the cube root of charge weight scaled distance, the square root of charge weight scaled distance, and other forms (Hossaini and Sen, 2004). Each of these scaled distances assumes relative contributions of the charge weight and the distance to the vibration attenuation. For example, the charge weight is assumed to have a less contribution to vibration in the cube root scaled distance than it is assumed in the square-root scaled distance. In reality, for different sites the relative contribution of the charge weight and the distance may be different and site-specific. This may explain that in some cases, the blast vibration data plots using these charge weight scaled distances are scattered. This could be largely due to the fact that the definition of the form of the charge weight scaled distance is not adequate for the particular site condition.

Jan 1, 2006

By Cathy Aimone-Martin, Kristin Dunlap Kolden

Blasting was conducted for the Army Corps of Engineers (Corps) in the Columbia River near Saint Helens, Oregon during 2009 and 2010 to deepen the navigation channel as a final phase of a dredging project to accommodate larger container ships. The Columbia River Channel Improvement Project (CRCI) required 4 months to blast and dredge 300,000 yd3 (229,366 m3) of basalt from the bottom of the channel to allow Post-Panamax vessels with drafts up to 50 ft (15.2 m) access to the Ports along the River. Explosives charges were limited to 90 lbs (40.8 kg) per delay for the protection of fish and marine life in the area. A fish mortality study and marine mammal monitoring program was also required by the Corps. Underwater overpressure monitoring was required for each blast and peak overpressures measured 10 ft (3.1 m) above the river bottom 140 ft (42.7 m) from the closest blast hole were not to exceed 70 psi (483 kPa) with a cautionary level of 40 psi (276 kPa). Specifications required sampling rates of 500k S/s and PCB Peizotronics tourmaline pressure sensors. The Corps granted permission to co-locate additional ceramic-type sensors at different sampling rates to design redundant monitoring systems 140 and 300 ft (42.7 and 91.4 m) from blasting and develop a site-specific overpressure attenuation model for the project. This paper presents the correlations of overpressure with cube-root scaled distance factors, a comparison of measurements using three different pressure sensor systems, and a discussion of blast design influence on overpressure measurements.

Jan 1, 2014

By Richard Dooley

This paper is one sided because it presents the problem, but not the solution. The problem of blisters (bubbles) and occasional tears in caisson liners occurred when blasting and we have not found a conclusive cause nor a preventive solution. (For back ground information, consult Techniques of Precision Blasting in the Excavation of Drilled Piers, by George Mosteller at the Sixth Conference on Explosives & Blasting Technique in Tampa, Florida 1980).

Jan 1, 1983

By Zoltan Susanszky

The total available energy in an explosive charge is seldom fully utilized in industrial operations. For this reason more explosive is normally used to perform a job than we would calculate. In an explosive detonation some energy is generated as waste energy which can not be efficiently used. This results in added expense and possible environmental damage. This waste energy can create problems in metal forming with explosives and during commercial underwater blasting operations.

Jan 1, 1976

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 Dworzak, Andrzej Biessikirski, Jozef Pyra

During the detonation process 20-30% of the energy is being consumed only on the quarrying pro-cess. The remaining amount of the energy generates harmful effects such as: shock wave, acoustic wave, fly rocks and ground vibrations. The ground vibrations effect is the most dangerous especially to structures which are situated nearby an open pit mine.

Jan 1, 2015

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

By Chuck Kliche, Bill Clements

This project involved the removal of the top of an old water supply reservoir tank for the City of Lead, SD by explosives. The general contract called for the removal of the concrete top without damaging the sides or floor of the reservoir. The option of a rock hammer was eliminated, due to the possibility of an unpredictable collapse damaging the sides or floor of the reservoir. Different blasting options were discussed between the primary contractor and the blasting contractor, along with the pros and cons of each. The primary contractor settled on the option of drilling the structure for blasting versus using shaped charges

Jan 1, 2007

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 Graeme Exelby

The 4" Wassara water hammer was originally developed by G-Drill AB together with Swedish Mining Company LKAB for their underground long hole production drilling. Sandvik Rock Tools AB is responsible for the introduction of Wassara worldwide.

Jan 1, 1998

By Robert Cefalo

Drill and Blast Engineer Abstract In 2019, the Bingham Canyon Mine, owned by Rio Tinto Kennecott Utah Copper Company, mined through the active underground that dewaters the pit. The active underground required the limitation of vibrations to avoid catastrophic damage or damage that would require work to the shotcrete and additional roof support. The surface design of the current sector next to and through portions of the active underground. The drill and blast group was required to test site law vibration parameters to ensure that vibration limitations were lower than limits set by the underground management team. Seismographs were used to validate the vibration prediction model and check performance of blast in areas of the underground. The bench conditions and limited pounds-per-delay created large obstacles for the blasting team, making it difficult for them to accurately load the pattern with the number of decks in the blast. Methods were used to improve the loading instructions and ensure that each hole achieved pound requirements based off of the distance to the underground that it was designed to protect. The project evolved from start to finish, and the process to estimate distances and loading improved to make the blast a more repeatable process for the size of the project.

By A B. Andrews

The use of sequential blasting techniques that combine surface and in-thehole delays has provided blasters with increased flexibility in blast design to promote good rock fragmentation and displacement while minimizing offsite blast effects such as air blast, flyrock, and ground vibration.

Jan 1, 1981

By G Dean Barrett

Just one year ago at the 1986 Annual Meeting of the Society of Explosives Engineers, Dr. Calvin J. Konya presented a paper entitled "Presplitting Granite Using Pyrodex, A Propellant.'' Since that time more evidence has been developed to support the concept that "...gas energy can be the principal splitting force and that the stress wave or shock wave is not necessary to cause the presplitting action to occur." Work done in Vermont and Georgia is presented, and the ability to split granite without causing radial cracking of the bore holes is demonstrated.

Jan 1, 1987

By Terri Jordan, Kenneth Hollingshead, Mary Jo Barkaszi

The Port of Miami, Miami-Dade County, Florida (Port) is the largest container port in the State of Florida. However, it is located in the center of a diverse ecosystem. Biscayne Bay surrounds the Port and portions of the bay have been designated as a National Park, a Florida Aquatic Preserve and a state Critical Wildlife Area. The bay is home to many protected, threatened and endangered species including the Florida manatee, five sea turtle species, American crocodile and bottlenose dolphin, in addition to important recreational and commercial fish species.

Jan 1, 2007

By Pierre DePasquale, Ricardo Chavez

Lowering of quarry energy consumption participates to answer both environmental and financial issues. The “EE-Quarry” European project, supported by the European Commission (EE stands for Energy Efficient), develops a new and highly effective modelling and monitoring Energy Management System technique to improve Energy Efficiency and move to a low CO2 emission rate in the nonmetallic mineral industry. Within this global quarry project, blast design, as the first link in the chain, has to be optimized in order to satisfy requirements of downstream operations. The authors have been developing and implementing an operational methodology using continuous field measurements and field adaptation methods for blast design. It drives the drilling and blasting work, aiming at a more energy efficient and environmentally friendly operation. Based upon actual local conditions (rock-mass assessment, face geometry, borehole deviations, etc.), blast patterns are optimized through a specific hole-by-hole blast design software. It provides a better and more consistent energy distribution, to achieve a better rock fragmentation, while avoiding explosive overconsumption. The software also calculates total energy inputs and the drilling and blasting contribution to Greenhouse Effect. Coupled with methodical fieldwork and variable density explosives, it has been leading to a real reduction in energy costs and greenhouse gas emissions. As the project is now reaching its final stage, demonstrations were conducted in various quarries around Europe. Several simulations were carried out and compared to the site data, in order to propose enhancements for the different phases (extraction, loading, hauling, crushing and transport) while bearing in mind the environmental impact of the quarry. This blasting methodology allows to assess the carbon footprint of drilling and blasting in conjunction with the downstream operations, thus to evaluate the global carbon footprint of quarrying. Copyright ©

Jan 1, 2015

By M Lemieux, R Mason

The SABREX blast modeling program was introduced to I.O.C.C.'s Carol Lake Iron Ore Project in December 1987. As part of CIL's Technical Services, SABREX was used to implement an optimization program designed to analyze and introduce various grades of MAGNAFRAC at a constant pattern while maintaining acceptable blast results.

Jan 1, 1989