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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 J R. "Dick" Daniel

One of the more common tasks in blast management is the adjustment of: shot geometry, explosive energy, and shot timing parameters to achieve changes in blast outcomes and costs. Many of these shot parameters, once a delayed blast is initiated, are modified by the development of new free faces which change the original or static input values to dynamic values. These newly generated dynamic values are easily calculated and find use in fine tuning shot adjustments and in rationalizing blast outcomes in a systematic manner.

Jan 1, 1996

By J R. "Dick" Daniel

One of the more common tasks in blast management is the adjustment of: shot geometry, explosive energy, and shot timing parameters to achieve changes in blast outcomes and costs. Many of these shot parameters, once a delayed blast is initiated, are modified by the development of new free faces which change the original or static input values to dynamic values. These newly generated dynamic values are easily calculated and find use in fine tuning shot adjustments and in rationalizing blast outcomes in a systematic manner.

Jan 1, 1996

By Koichi Kurokawa, Takeo Ueda, Yoji Tasaki, Masashi Nakano

We have developed a new firing system which simplifies the handling and extensively increases the safety in electric blasting operations. Based on the principle of the transformer, this system is operated as follows: When a high frequency alternating current pulse (70-110 kHz) is applied to the lead wire and connecting wire (primary circuit), magnetic flux is generated in the transcore, and an induced current flows through the looped leg wire of the detonator (secondary circuit). Then the detonators are ignited by the induced current.

Jan 1, 1986

When CIL presented their new theory of the Breakage Process and Delay Blasting at the 74th Annual Meeting of the CIM in 1972(1), there was hardly any open pit operation in Canada that was using longer than 25 msec. delays. To the contrary, 10 and 15 msec. surface relays were common, which in our opinion were no delays at all for open pit blasting.

Jan 1, 1979

By Lifeng Li, Jhon Silva-Castro

"Signature Hole Technique is one method to assess the vibration waveform of a production blast.Methematically, it is the convolution between a prior measured waveform of a single blast hole (signature) and a given time delay sequence (comb function). Being an advantage, the inverse operation of convolution, known as deconvolution, can be used to estimate the signature."

Jan 1, 2017

By Abraham Lindo

Panama’s current economical growth demands an increase in electric power supply; projected energy supply for 2012 exceeds the demand by as little as 2%. In an effort to comply with the demand, several different hydroelectric projects, promoted by the government, are currently under construction and each of them vary in generating capacity, construction design and complexity.

Jan 1, 2013

By Dale Ramsey

Located in the Chestnut Ridge Mountains of Southwestern Pennsylvania, the Casparis mine named for the founder Kenneth Casparis operated from 1916 until the early 1950. producing crushed stone for construction and railroad ballast. The rock was transported by aerial buckets to a railroad tipple nearly 1000’ (304.80 meters) below the mine. The mine property is now owned by the Pennsylvania Game Commission and is located in the Loyalhanna limestone seam with 4 primary entries that are approximately 40’ (12.19 meters) high by 30’ (9.14 meters) wide and extend over 2 miles (3.22 kilometers) into the mountain.

Jan 1, 2006

By Marco Antonio Falquete

Conventional detonators and blasting caps make use, as igniters, of flame-shock-, andfriction-sensitive primary explosives, such as lead azide, lead styphnate, mercury fulminate, etc, most of them severe toxic and environmental contaminants. Sensitivity of primary explosives is one of the main causes of injuries and fatalities in explosives industry and in field applications. Intense research for a reliable, safe, and environmental-friendly non-primary-explosives detonator was conducted by the industry in the last years. A new detonator is presented, containing no primary explosive, employing only environmental-friendly substances while keeping reliability of performance. A series of performance tests is executed in prototypes of different output energies, including initiation by flame, shock tube, thermo tube (IBQ’s proprietary spark-generating tube, presented at 2005 ISEE Conference), energy transfer reliability, and extreme environmental conditions (according to MIL-STD 331B, test C1 standards). Results are compared, when pertinent, with standard blasting caps of different energy outputs, and with standard primary explosives.

Jan 1, 2007

By S. Green, R. Yang

Blasting is a commonly used method for rock fragmentation in mining operations for mineral extraction. It involves breaking the rock mass into small pieces, and ideally creating micro fractures within the small pieces. Such micro fractures could significantly reduce the energy required for subsequent processes like crushing and comminution. Additionally, micro fractures would enhance the rock-fragraments fluid permeability thereby enhancing desired chemical reactions during certain processing operations. This paper presents recent developments of the Multiple Blasthole Fragmentation (MBF) model, which simulates blasting rockmass fragmentation. The MBF model allows estimating rock strains experienced during the blast, for various blast design parameters and geometries. The intent is to correlate these strains with created micro fractures in the blast rock fragments. Adjusting blast design parameters in the MBF model of explosive loading and delay timing allows blast optimization. Such optimizing would create desirable strains to enhance micro fractures within the rock fragments. This would improve mining operations by enhancing downstream operation efficiency, thus reducing costs.

Jan 1, 2024

By Julia Creasey, Natalie Hodgson, Claire Ward, Craig Davies, Helen Sarginson

"Emulsion explosive producers are attempting to lower the cost of emulsion production by using lowquality ammonium nitrate in emulsion formulations. Low quality ammonium nitrate contains additivessuch as anti-caking agents and crystal modifiers which contaminate the emulsions causing instability. This presents a need for an effective emulsifier that will maintain emulsion stability under thesechallenging conditions."

Jan 1, 2017

By Qingshou Chen, Gongbo Li, Hengqian Ran

A method for safe fracture of rock, concrete and other brittle solid material using dynamic water pressure by explosion is provided. The propagation of the pressure is studied with Allievi water hammer theory. Wave equation and velocity formulas of the pressure propagation are shown. The dynamic water pressure is tested in the lab. The propagation of the pressure is simulated by MMIC-2D. The results of fracturing rock in the lab and on a quarry are presented.

Jan 1, 2000

By James R. Kennedy

The recent drop in world gold prices is driving many northern Nevada underground gold mines to look for new ways to improve and enhance current mining operations. Continuous improvement programs at these mines are finding the means to increase mine productivity while reducing total production cost. This paper looks at developments in the drill and blast program at Independence Mining Company’s Murray mine.

Jan 1, 1999

By Erik Nygaard

Ammonium nitrate (AN) is the main ingredient in most industrial explosives, but it is estimated that as much as 80-90% of the global annual production is used as fertilizer [14, 25]. Over the last years AN has been involved in several accidents and used in criminal bomb making. Therefore authorities and legislators worldwide have given it special attention. This paper is divided into three parts: • The first part will focus on the accidents with AN that have occurred over the last years and possible scenarios based on official investigations. • The second part covers safety and security related issues. • The third part will summarize new legislation that is coming both within European Union (EU) and also on a global scale.

Jan 1, 2006

Current research in comminution includes efforts to increase the efficiency of mineral processing systems and reduce the amount of electrical energy needed for size reduction. In most mining operations, comminution begins with blasting. Normally, blast design focuses on loosening material for excavation and sizing the product for efficient haulage. It is likely that blasting also results in internal damage to rock fragments within the blast pattern which may provide subsequent comminution benefits. If substantial comminution benefits exist, appropriate modification to blast pattern design may reduce the overall electrical energy needed for mineral liberation.

Jan 1, 1996

By Catherine Johnson, Barbara Rutter

The shock tunnel located at the Missouri University of Science and Technology Experimental Mine is 65 feet 9 inches (20.0406 m) in length. The tests performed inside of this tunnel are either arena tests or shock interaction and transfer (SIT) tests. Arena tests simulate a large open air blast, with lower explosive weights, by elongating the impulse of the blast wave. SIT tests are conducted to determine how the produced shock wave interacts and transfers its energy into a target object located at the end of the tunnel. The target used in this research is multilayered, with each layer being a different material. The targets are 2 ft. by 4 ft. (0.6096m by 1.2192m) pieces of Medium Density Fiberboard (MDF), DOW polystyrene foam insulation, and gypsum drywall. The order of these materials varies with each test. This shock tunnel is unique, because the geometry changes along its length. To fully understand how the shock waves are affected by these changes, a working model was needed. The second purpose of this model is to confirm the maximum charge size of 400 grams (14.11 oz.) of C4 that can be detonated inside the tunnel without causing damage to or failure of the tunnel, thus reducing the amount of time needed in downtime and repair. The model predicts pressures in various locations both within the tunnel and the attached target, thus assisting in determining where failures would likely occur. In the process of generating this model, several problems were encountered, including filling the tunnel with air, meshing the complex geometry, and creating the tunnel in a CAD system. This paper will discuss how these problems were solved. A working model was created by using ANSYS Explicit Dynamics and ANSYS Autodyn. The tunnel geometry file was created using SolidWorks and includes the complex geometry changes along with the target and its mount located at the end of the tunnel. The results produced by the model were compared to the field SIT tests. The comparison of the results from both the model and the experimental testing showed a similar trend in the pressure traces.

Jan 1, 2018

By Ulf Nyberg, Changping Yi, Daniel Johansson, Håkan Schunnesson

To investigate the non-ideal detonation properties of aluminized emulsion explosive, a series of tests for an emulsion explosive with 5% aluminum powder additive were carried out with mortar confinement. The velocity of detonation (VoD) and the curvature of the detonation front for different charge diameters were obtained from the tests with a high-speed camera. The burning process of the aluminized emulsion explosive has been modelled with the ignition and growth (I&G) flow model in the LS-DYNA code. A routine based on the optimization program LS-OPT code was developed to identify the parameters in the burning rate function with the detonation velocities and the front curvature radii from two tests. A Perl code was implemented in the routine and was used to calculate the VoD, fit the detonation front and obtain the detonation front curvature radii. The calibrated parameters were used to predict the VoDs and the detonation front curvature radii for the rest cases. The results indicate that both the VoDs and the detonation front curvature radii from the numerical modelling are in good agreement with the experimental results. The numerical results also indicate that the variety of the burn fraction and the peak pressure with the change of charge diameters is reasonable with the calibrated parameters.

By Wang Zhong Qian, Liu Hui

The paper proposed a fractal and damage model for rock-breaking by blasting, which assumed that the process of rock-breaking results from intrincent fractal development and the accumulation of damage. Remarkably, the process is of fracture character. Based on the model, a computer program is compiled to calculate the 3-dimension damage distribution in blasting crater. Trial results agree well with the predicted results, showing the model set up in the paper is sound.

Jan 1, 1997

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 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