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By Francisco Sena Leite, Vinicius Miranda

Mine blasting is directly associated with ground vibration. If these affect critical structures (buildings pit walls, etc.) they must be mitigated to reduce the environment and social impacts. Vibration monitoring and control is one of the most important procedures in blasting because it will impact short and long term incidents associated with this blast effect. Technology moves ever forward, and today we have personal devices that are equipped with an array of sensors, for that reason the authors decided to investigate the possibility of using a personal device to do vibration control. This case study compares the same blast measured with a traditional seismograph and a smartphone. To validate this new methodology, attenuation laws were built with data from a traditional seismograph and a smartphone application. Predictions were also made prior to a set of blasts. Residual analysis was used for data validation from the two different sources. From the performed analysis, to prove the validity of this new methodology, the normality tests for statistics residues analysis proves that it is possible to infer that the model has a null residual mean and a small residual error. The achieved results show the accuracy of these devices, the authors pretend to show the potential of this equipment and open a completely new door for vibration analysis.

Jan 1, 2018

By Park Yun-Seok, Jung Seung-Won, Hwang Nam-Sun, Song Jin-hyuk, Kim Young-ho

This study proposes a new blasting vibration estimation formula that reflects the vibration reduction characteristics of electronic detonators, which are not considered in the current MOLIT blasting vibration estimation formula. Test blasts were conducted across six types of Korean open-pit blasting designs. The results of the test blasts showed that the K value for electronic detonators decreased by approximately 30% compared to electric detonators. Predicted Peak Particle Velocity (PPV) analysis indicated a reduction effect ranging from 30% to 31% across various types. By incorporating this reduction in the K value into the MOLIT blasting vibration estimation formula (K=200), a new electronic detonator blasting vibration estimation formula (K=140) was proposed. Using this new formula, the blasting damage range (R) was calculated under various vibration limits to evaluate constructability improvement. On average, the R value for electronic detonators decreased by about 17%, with significant reductions of around 41% observed for TYPE I under certain vibration limits. In conclusion, the adoption of electronic detonators in open-pit blasting operations improves blasting efficiency, reduces economic costs, and significantly enhances constructability. Electronic detonators have demonstrated superior performance in minimizing damage to safety facilities compared to traditional electric detonators, thereby proving their practicality and effectiveness in blasting operations.

Jan 21, 2025

By Daniel Roy, Chris J. Preston, Ron J. Elliott

This paper discusses the use of pressure transducers in water filled boreholes in conjunction with surface mounted geophones to gather field data for in-situ dynamic rock properties determinations. A high speed collector is used to capture the data in the field. The calculated P and S wave velocities and rock density measurements are used as input into the Blastcalc program where the values of Young`s Modulus and Poissons Ratio are calculated. The rock properties information is used along with geological structural data and explosives properties in a 3-D blast modelling program to calculate predicted fragmentation distribution and other blast performance criteria based on the proposed blast design.

Jan 1, 1996

By Roger L. Keller

Cautious, productive blasting is employed in the adaptation of a mobile crushing system extending into a highway through cut. In Hong Kong's final chapter of infrastructure development in preparation for handover of sovereignty, the vital link to the new governing country, The People's Republic of China, is now being completed. The Ting Kau approach and Tai Lam tunnel involves the removal of 6 million cubic meters of rock by drill and blast means. For the main-cut excavation (because of removal Iogistics) a unique adaptation of a Lokotrack crushing and conveyor transfer system is being used. The characteristic narrow working area associated with through cuts, positioning of equipment, and production demand place many limiting factors on blasting. Add to this the strict criteria set by the local regulatory body, the Hong Kong Mines Division, and nearby vibration limiting structures (13mm/sec), has led to highly cautious, fine-tuned blasting.

Jan 1, 1998

By Tom Hanke, Joe Strobbe

The 80 year old Theodore Roosevelt Dam built in a scenic canyon near Globe, Arizona is currently undergoing a major renovation. The old stone dam, built by hundreds of skilled stonemasons, is being covered with a new concrete face that will increase the dam height by 77 feet. The renovated dam will improve flood control and provide increased electrical power and recreation area. The contractor, J.A. Jones is constructing the new dam and powerhouse for the Bureau of Reclamation.

Jan 1, 1993

The quiet banks of the Maumee River in Toledo, Ohio, received a wake-up call July 16 as two smokestacks in the Marina District were leveled with dynamite. B&B Wrecking, Inc. of Cleveland contracted the project with the city to bring down the twin stacks, both measuring over 250 feet tall. The structures were part of the Toledo Edison Steam Plant and were erected nearly a hundred years ago. A week’s worth of preparation went into final planning, drilling and loading holes with over 80 pounds of explosives. The felling went precisely as planned as onlookers cheered as the stacks were reduced to rubble.

Jan 1, 2015

By Scott G. Giltner, Alex Schwenk

An iron operation sought to extend the life of the mine by conducting a major pit pushback in an area close to several public structures and the neighboring town. The result of the pushback would make millions of tonnes of ore available for mining allowing many additional years of taconite mining. This paper discusses the initial development blasts conducted for the pit pushback. For the development blasts, it was determined that no fly rock should leave the mine site and that the blast vibrations should be as low as possible, but specifically under 19 mm/s (0.75 in/s) at a nearby sewage treatment plant. One issue complicating the blast design was the variation in hole depth within any given blast. For the initial sinking shot, the hole depths varied from 6.4 m (21 ft) to 12.5 m (41 ft). In the subsequent blasts the hole depths within each blast could vary up to 5.8 m (19 ft). Various tools were employed to design the blasts to ensure there was no fly rock and that the blast vibrations were as low as possible. UAV surveys of the blast areas were conducted to provide a 3-D representation of the free faces and bench surface. The 3-D point cloud produced from this was used to measure the shape of the free faces. Once the shape of the free faces was quantified, it was possible to establish proper placement of the crest holes and develop a custom explosive load for each blast hole. In addition, signature hole analysis was performed for each blast to determine the optimum delay time that balanced the need for minimal vibration, prevent fly rock, and a well fragmented muck pile. Electronic detonators were applied to achieve the necessary control of the blast that balances these three concerns. The results of the seven blasts conducted to date provided the desired results. The peak vibration level at the sewage treatment plant for the seven blasts was 10 mm/s (0.40 in/s). The only fly rock occurred when there was a miscommunication in the blast design resulting in under burdened holes on the front row. To date, the mine has been able to safely expand the pit into an area that will add many years to the mine life. The muck piles have been well fragmented with reports from the shovel that they have all dug well.

Jan 21, 2025

By Maja Franjic, Ian Tolliday, Chris Collins, James Wiltshire

Ammonium Nitrate Emulsions (ANE) are a large segment of the explosives market for the mining industry. These emulsions are generally designed to be very stable but when breakdown does occur, removal of the resulting thick, crystallized material can be difficult, hazardous, time consuming and costly. A heavily crystallized emulsion cannot be pumped, so manual removal often becomes necessary. Buildup of semi-solid layers of crystallized emulsion can occur in bulk storage tanks or in truck compartments. In these situations, a manual cleanup involving hazardous confined-space entry and a significant amount of downtime is usually required. Once the crystallized emulsion is removed from the equipment, there is very expensive disposal of the resultant waste via a licensed trade-waste company. A much more desirable solution for dealing with waste emulsion is to completely break the emulsion, allowing the oxidizer and fuel phases to separate into two distinct layers. These layers would then be readily pumpable and could be disposed of much more economically. It may even be possible that the separated oxidizer phase could be repurposed as fertilizer and the fuel phase could be used to manufacture granular ANFO explosives. There are some existing products on the market for breaking emulsion explosives, but these generally need a high degree of mixing into the emulsion to achieve adequate breakdown. The aim of this study was to identify surfactants systems (demulsifiers) capable of effectively breaking a range of waste emulsions with minimized agitation. This paper describes the development and performance testing of novel demulsifier products. The test work involved a comprehensive series of laboratory screening tests, where the demulsifier formulations were optimized. A highly efficient formulation was identified, and field trials were conducted on real world, full-scale waste emulsions. Results will be presented that demonstrate a viable solution for the disposal, and potential re-use, of waste ANE in the explosives industry.

Jan 21, 2025

By Scott E. Winston, Spencer C. Watson

Dynamite is a generic term for a variety of high explosive formulations containing a blend of liquid and solid nitrate esters co-mixed with solid oxidizers and carbonaceous fuels. Dynamites can be divided into general classes of nongelatins, semi-gelatins, and gelatins which vary as to their detonation rates, densities, and water resistance. There are also numerous products within each classification depending on their utilization or on their permissibility in various types of underground mining operations.

Jan 1, 1985

By John R. Schuring, Walter Konon

The 2.0 in./sec. peak particle velocity criterion traditionally used to protect structures from blast induced vibration damage is non-conservative for landmark structures. Various factors which must be considered in establishing vibration criteria for landmark structures are discussed. Existing criteria by past investigators for this class of structure are presented.

Jan 1, 1984

By Feng Shuyu Yang Nianhua

According to the results of high speed photography tests, particle velocity measurement tests and the digital calculation with TP2 software, the shape of shock wave, the declined laws of the shock wave propagation speed and the peak particle velocity are described and analyzed in detail. New viewpoints about the theories of blasting fragmentation based on analysis of the progressive pictures of the fracture region are given. The formula for calculating the depth of fracture regions is established on the basis of the new viewpoints.

Jan 1, 1997

Blasting in a development heading or breasting operations starts from a cut. The void created by the cut provides a free face for the remainder of the round. It is the most critical part of the round because the later firing charges cannot pull to the desired depth unless the cut comes out as planned. The Burn cut is most commonly used in Canadian mines.

Jan 1, 1995

By Mike Cammack

Western South Dakota is predominately an agricultural area, with exception of the mining and timber industries in the Black Hills region. With precipitation rates averaging below fifteen inches per year, water is a precious commodity to the livestock industry. There is a constant demand for the construction of earthen water storage facilities (dugouts) to catch snow and rain runoff, or developing natural springs.

Jan 1, 1993

By Stephen John Brace

Increasingly, electronic blast initiation systems are being made available to the mining and construction community, both in South Africa and internationally. Indeed, in some parts of the world, perhaps half a dozen electronic products are being used, with a choice also of shock tube, electric and fuse and igniter cord systems. As these developments have taken place, improvements have been made in safety, reliability and accuracy, so much so that high performances in all these areas are now expected. However, disadvantages often seen by customers, other than : higher price, are decreased user-friendliness and loss of flexibility.

Jan 1, 1998

The most common method for identifying the potential for blast damage is the peak particle velocity. But this can depend on many factors such as the type of blast, explosive, confinement, timing and the rock mass. The value must then be used to estimate damage. But the amount of damage will depend on the rock mass quality and the excavation size and shape. The amount of damage that can be accepted will depend on the purpose of the excavation. This paper presents a logical, but very approximate, procedure that the mining engineer can follow in order to assess the potential for damage in the control of that blasting.

Jan 1, 1987

By J P. Tidman

The problem of blasting fragmentation has received a good deal of attention in recent years. Progress by the scientific method requires a good set of experimental data as a benchmark to test models. Recent models have become so complex that it is not possible to use the results of field data because the complete set of parameters needed to describe the rock and/or explosive are not available.

Jan 1, 1991

By Lee Julian

Ground vibrations generated by mine blasting must be controlled to comply with legislation and to protect sensitive local or site infrastructure. The consequences of exceeding imposed limits can range from negative publicity to structural damage to infrastructure. It is imperative that vibrations are controlled without compromising fragmentation and delivery of blasted inventory. General practice is to reduce the charge weight and the blast size as blasting approaches the sensitive structures; however such an approach results in blasting smaller volumes more frequently which places greater pressure on production to meet their targets.

Jan 1, 2014

By Andrew Theobald, Peter Dare-Bryan, Trevor Byers

The use of advanced modelling techniques and the timing flexibility of electronic initiation systems allows for unprecedented control over blast outcomes as shown in several complex blasting problems experienced by the open pit operation Xstrata Ernest Henry Mine (EHM) in north-west Queensland, Australia.

Jan 1, 2010

By P. R. Mohanty, Kaushik Dey

Blast-induced tunnel overbreak prediction in the past has been based on peak particle velocity measured far from the blast site with necessary extrapolation. This has often resulted in suggesting higher damage threshold levels of Acceleration/PPV for overbreak prediction (Bogdanhoff, 1995, Holmberg and Persson, 1997, Murthy and Dey, 2002). These, site-specific far-field blast vibration studies, have also revealed that predicted PPV levels for overbreak could lie in the range of 700-5000 mm/s, an extremely wide range to generalize. Experimental blasts were conducted, in an underground metal mine located in eastern India, with an objective to study the level of acceleration /peak particle velocity generated in tunnel blasting. Accelerometers and tri-axial geophones with measuring ranges upto 500 g, 254 mm/s respectively, were mounted on the tunnel floor close to the blast face, with sensor distances varying from 15.25m to 36.10m. Due to straight faces the measuring distance could not be reduced further anticipating, in particular, cable damage. The equipment used was of M/s Instantel Inc., Canada. The blast pattern used was burn cut with large dia relief holes providing the required free face. The blast hole depth was 1.8m. Tunnel overbreak was measured using a telescopic offset rod fabricated at Indian School of Mines, Dhanbad, India.

Jan 1, 2004

By Paul Worsey, Gillian Worsey

The basic blasting class at Missouri S&T blast in the quarry at the experimental mine in preparation for the International Intercollegiate Mining (Mucking) Competition in April 2014.

Jan 1, 2015