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By Jerry Wallace

A highway bridge demolition project to allow shipping access to a new container port in Puget Sound ran into trouble when contract-stipulated mechanical means of demolition failed. Blasting was then employed under less than ideal conditions and was successful.

Jan 1, 1999

By Jack Eloranta

Optimization of blasting requires the comprehension of processes including drilling through milling. The author has previously considered the role of powder factor in relationship to downstream processing costs. Recent modeling done by Lownds provides improved prediction of fragmentation based on the distribution and level of blast energy. Many recent studies have indicated improved downstream costs due to higher powder factor. However, changes in powder factor are accompanied by changes in pattern. The purpose is to segregate the effects of higher powder factor from powder distribution. This paper will attempt to use typical Mesabi Range iron ore parameters and costs to illuminate the subject of total process optimization.

Jan 1, 2001

By Dennis E. Mitchell

The need to develop and field explosive, pyrotechnic and propellant initiating systems that have high reliability and extraordinary safety requirements has led to the exploration and development of several materials and initiation systems at our laboratories. Our approach to initiating device development encompasses five main areas; energetic materials development , device physics, theoretical analysis and model development and experimental verifications

Jan 1, 1995

By Robert B. Hopler

"The story of packaged explosives begins with the use of black powder (also called gunpowder) in mining. Although discovered in the 13th century, it was not until 1627 that the first records of use in mining is recorded. It took until the early 1800's before its use began in underground coal. Althougha free-running, granular material, its recommended (and safest) manner of use was for the miner to pour it into ready-made or onsite formed paper bags prior to insertion into the borehole. This was absolutely necessary in horizontal or upward-slanting holes."

Jan 1, 1991

By David G. Paton

"Electromagnetic surveys were conducted at the BXL Bulk Explosives Limited Mixing Plant andsurrounding area to characterize runoff from the site and possible impacts of salinity. The BXL Plant is located at the edge of a depressional area and any escape of soluble ions, such as nitrates, would have ended up in the slough to the west of the plant. Two electromagnetic (EM) instruments were used in the survey. A Geonics EM 3 1 was used in October 1997 and in June 1998, a new multifrequency instrument, a GSSI GEM 300 was also tested. Both instruments were individually mounted on a plastic sled with Teflon runners and towed with an ATV quad. Position was determined using a Trimble Pro XL global positioning system (GPS) with a real time correction mode Landstar receiver for an accuracy of about *l m. Both GPS and EM instruments were set to collect data at 1 second intervals. The quadrature maps for both instruments showed essentially the same information, namely of very high conductivity, appearing to emanate from the mixing plant. The levels of conductivity were highest where the saline water appeared to pool, at the southern end of the slough. Soil sampling locations were identified from the EM maps and navigated to using the real time GPS. Composite samples were collected by hand using a Dutch auger, from two locations, in increments of O-1 5, 15-30, 30-60 and 60- 90 cm. The analysis of the soil samples indicated a complete absence of nitrate or ammonium ions; the major anion was sulphate, indicating naturally saline subsoil conditions. The GEM 300 made the collection of data more efficient, as only one pass was required to collect the data from four depth intervals. The EM survey combined with the real time GPS allowed rapid characterization of the site with respect to soil salinity and proved to be cost-effective for Phase l/ Phase 2 site assessments and targeting sampling locations."

Jan 1, 1999

By Donald Jonson

The Arlanda Link project is for the time being the most interesting project in Sweden, concerning rock and blasting technology. The total amount of rock excavated beneath Arlanda airport comprises 800 000 m³ divided in four parallel tunnels measuring a total length of 8,5 km, with a rock covering of only 5-15 m between the tunnel roof and existing terminal buildings.

Jan 1, 1997

By Gordon K. Jorgeonson

Much of the modelling of blasting operations has been devoted to simulating blasts in open pit mines and quarries . This has been the most obvious application and has been reported in many papers and discussions in the past.

Jan 1, 1990

By Dong-Hyun Kim Kim, Tai-Ro Lee, Young-Hwa Seo

Overbreak occurred inevitably in a tunnel excavation, is the main factor for increasing cost and period in tunnel projects. Furthermore the damage to the remaining rock mass related to the overbreak can give rise to a serious safety problem in tunnels. As a rule of thumb, causes for the overbreak are inaccuracy in drilling, the wrong design of blasting and selection of explosives, and heterogeneity in rock mass. Specially, the geological features of the rock mass around the periphery of an excavation are very important factors, so a lot of research has been conducted to describe this phenomena. But the geological rockmass classification for the overbreak and the method for decreasing the overbreak have not been fully established. Besides, the technical improvement of the charge method is needed as explosives for the smooth blasting have not functioned efficiently. In this study, the working face around periphery of an excavation has been continuously sectionalized to 5~ 6 parts, and the new Blastability Index for the overbreak based on 6 factors of RMD(Rock Mass Description), UCS(Uniaxial Compressive Strength) JPS(Joint Plane Spacing), JPO(Joint Plane Orientation), JPA(Joint Plane Aperture) and FM(Filling Material) is proposed to classify sections of the working face. On the basis of this classification, the distance between contour holes and the charging density are determined to minimize the overbreak. For controlling the charging density and improving the function of explosives, the New Deck Charge(N.D.C) method utilizing the deck charge effect and detonation transmission in hole has been developed.

Jan 1, 2003

By Randy Wheeler

The importance of having full wave form information for recorded blast events cannot be overstated. Knowing the peak particle velocity and the frequency at the peak are the tip of the iceberg. This presentation will focus primarily on using the FFT (fast Fourier transform) for detailed frequency analysis. Employing linear superposition to evaluate timing effects on amplitude and frequency will be discussed.

Jan 1, 2005

By Shazad Hosein, William J. Birch, Robert Farnfield, David Jameson, Catherine E. Johnson

The current and consented quarry workings at a slate quarry in North Wales {UK} intersect old long abandoned underground slate mine workings. The old underground slate mine contains the remains of World War II buildings used to house artworks to protect them from war damage. Over the past 20 years, there have been a number of roof falls in the old underground slate mine, which have damaged the buildings and make general access unsafe. From observation of the timing of these falls, they occurred in the mid 2000’s. The purpose of the exercise was to determine the possible relationship between blast vibrations experienced on the surface and those experienced on the roof of the abandoned mine caverns. Thus preventing the need to regularly monitor in the old mine workings. In order to achieve this, a rigorous geotechnical assessment of the stability of the caverns was undertaken by a fully qualified Geotechnical Engineer. Once it had been determined that it was safe to do so, 3 “MEMs based” blasting seismographs were attached to the roof, in accordance with the instruction of the geotechnical engineer. In addition, 8 “MEMs based” blasting seismographs were deployed at various locations on the surface. The trial blast comprised of 51 blastholes, with charges varying between 46kg [101lbs] and 124kg [273lbs] of bulk emulsion explosive. The blastholes were in 4 rows of holes. The blast was connected using shock tube 25ms, 33ms and 65ms delay period relay detonators. The minimum distances from the blast to the surface and underground monitoring points were 78.1m [256 ft] and 114 m [374 ft] respectively. The results from the three underground monitoring locations in terms of resultant peak particle velocity was 4.42 mm/s [0.174in/s], 3.47 mm/s [0.137in/s], and 4.69 mm/s [0.185in/s]. In line with previous research, it was determined that the underground results [when compared on a “like for like” basis in terms of scaled distance] were lower in amplitude than the surface results. In this case by a factor between 0.47 and 0.87, averaging 0.68.

Jan 21, 2025

By Felipe França Sitonio

Parameter’s control of explosives used in blasting operations have become more relevant over the years, bringing a better understanding of detonation performance. Giving into consideration that bulk emulsion density’s variation reflects directly on blasting results due to its importance in product sensitivity and velocity of detonation (VOD), blast designs are conducted assuming that cup density measurements are reliable and explosives gassing agents will perform as per specifications. Nevertheless, confinement conditions in boreholes like temperature, presence of water and surrounding circumstances of rock mass are often neglected on predictive modelling and off-site measurements. This paper describes the assembly of a device equipped with pressure sensors and its utilization in confined boreholes of an open pit mining operation, aiming to obtain in situ monitoring of density variation in several explosive columns. After we developed a software to get and process data of a hardware prototype and the device functionality was validated in water, oil and quarry mining experimental trials, 7 of 291 boreholes in a gold mine operation were chosen to be monitored with two probes each, placed at the top and at the bottom of the explosive column profile. The results obtained enabled a comparison between the bulk emulsion density variation when acting in different environments, since we selected boreholes with diameter of 101.6 mm (4 in) and 139.7 mm (5.5 in) and some with presence of water. Besides the increase of explosive density with depth related to hydrostatic pressure increase, we found an overall error of 6% in cup density measurements when compared with sensors placed at the bottom of boreholes and 2% when compared with sensors placed at the top of explosive column. These findings provide detailed insights into how bulk emulsion explosives behave in different circumstances including depth and borehole diameter, giving the opportunity to re-evaluate blast design parameters such as its geometry, sequence pattern, charging profile and explosive composition.

Feb 2, 2020

By Peter Moser, Frank Chiapetta, Sacha Diaj, Florian Bauer

Good toe breakage and a flat working bench after blasting are important parameters to achieve a high productivity during material loading and reduce the necessity for secondary blasting. Good toe breakage requires a proper burden – side spacing design and a suitable sub-drilling. With unfavourable jointed rock mass conditions the use of horizontal bottom holes still can be found as common work practice even that this is associated to high risks.

Jan 1, 2009

By Ray Patterson

A planned modification to a cement kiln at the Holnam Portland Cement Plant near Florence, Colorado required the removal of a ring of cast-in-place (CIP) refractory lining. The CIP lining was approximately 14 inches wide, 12 inches thick and 38 feet in circumference.

Jan 1, 1999

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 Chanhwi Shin, Hyeongmin Kang

Mine optimization is a key strategy in the mining industry that focuses on improving the efficiency, productivity, and sustainability of mining operations. To achieve mine optimization, digitalization is essential for modernizing mining operations and attaining optimal performance. Due to the importance of mine digitalization, various software and platforms have been released to support this effort. Furthermore, by integrating these advanced technologies, mines can enhance processes, leading to significant economic and operational benefits. However, integrating data from various sources and collaborating across different platforms remains a significant challenge in the mining industry. Generally, data for mine optimization, such as mapping, smart drilling, FMS (Fleet Management Systems), fragmentation analysis, or vibration analysis, are collected and analyzed separately on different platforms. This separation makes it difficult to aggregate and utilize data comprehensively for overall mining process optimization. During the digitalization process, obstacles arise due to these complexity, variability, and sharing issues of data across different maker, sources, and methods. These challenges highlight the need for seamless integration to achieve optimal mining operations. Thus, this study applied a total solution that can cover the entire Drilling and Blasting (D&B) processes. The blast design was performed using actual terrain mapping data, and drilling and charging were conducted following a guide based on the blast design plan. After blasting, loading and hauling distances and fuel consumption were measured, and fragmentation for each blast was evaluated. All measurement tasks were automated to minimize human error. By collecting all data in one server, it became possible to perform an overall evaluation for each blast, allowing the identification of optimal values. In conclusion, to evaluate the optimization effects for each mining process, one month of integrated data collected on a single server was used. Compared to the period before the Total solution was implemented, there were notable improvements: a 25% enhancement in hole spacing, a 60% improvement in floor flatness, a 23% reduction in average fragment size, and a 19% improvement in fragment uniformity. Regarding cost savings per blasting volume, the improvements were 11.7% in drilling, 9.3% in explosives, 7.6% in loading, and 17.5% in hauling.

Jan 21, 2025

By Robert Hopler

Of the common causes of the larger mine accidents, such as falls of roof and coal, gas and dust explosions, mine fires, and the misuse of explosives, all of which are often closely related, each must be studied and fought in a manner peculiar to itself. The last mentioned, the misuse of black powder and other explosives, is sometimes considered the least important of these causes of mine accidents; but its importance is much greater than the statistics indicate, for the reason that the misuse of explosives is the true cause of many of the fatal mine fires, gas or dust explosions, and falls of roof that are credited to other causes.

Jan 1, 2012

By Donald Hurd, James Rowland, Richard Mainiero

In previous conferences the authors have reported on toxic fumes generated by the detonation of ANFO. The research reported here extends the earlier work to include an emulsion blasting agent and ANFO/emulsion blends. Explosive mixtures were shot in 4-inch Schedule 80 steel pipe (outer diameter 4.50 in (11.43 cm), inner diameter 3.83 in (9.72 cm)) in a chamber in the experimental mine at the Pittsburgh Research Laboratory (PRL). Following each shot, the fumes in the chamber were analyzed using on-line instrumentation.

Jan 1, 2001

By Virgil J. Stachura, Calvin L. Cumerlato

The U. S. Bureau of Mines is conducting research on blasting methods that reduce highwall overbreak and the associated rockfall hazards. This paper presents the results of tests using a low-density water gel to improve the quality of air-decked presplit blasts at a surface coal mine in New Mexico. The explosive's specific gravity averaged 0.50 and was bulk loaded using a modified truck which injected the gassing agent. Reductions in overbreak and resulting rockfall were achieved in comparison to a highwall presplit with ANFO. The test sections used 15° angled blast holes and resulted in 1,119 m (3,672 ft) of air deck presplit highwall using a low-density water gel which was then compared to 894 m (2,934 ft) of highwall shot with an ANFO air decked presplit design. The total quantity of explosives per hole ranged from 68 to 113 kg (150 to 250 lbs) and the 27 cm (10-5/8in) holes were 19- to 33-m (62- to 108-ft) deep on 5.5 m (18-ft) centers. Periodic visual examination and photographic surveys of the highwall test areas were used to document the amount of rockfall. In addition, laser profiles of selected sections were conducted to further delineate the damage and highwall contour differences.

Jan 1, 1995

By Douglas A. Anderson

The US Bureau of Mines, in RI 8507, has shown that blast vibrations at low frequency are more likely to cause damage and complaints than those at higher frequency. Since that publication in 1980, the Office of Surface Mining and many state and local regulatory authorities have incorporated frequency in their regulations for acceptable ground vibration from blasting. Even when frequency is not explicitly stated in regulations, it may become an issue in hearings or in court.

Jan 1, 1992

By Kevin Dunfield

The Deltadet System is composed of: The Deltadet II electronic Detonator. A Field Terminal to create, modify or simply execute an existing blasting sequence. The radio remote controlled option is composed of a Base Station to program, calibrate and initiate the EDDs plus a Blasting Box to send commands to the Base Station. Blasting lines to connect the EDDs to the Base Station (100m) and Visual Blast software to create or modify a blasting sequence.

Jan 1, 2004