Search Documents

By Cameron McKenzie, John Heilig, Patrick Andrieux, Andree Drolet

It is widely accepted that both underground and surface blasting operations can de-stabilise excavations to the point where it can threaten the feasibility of mining through personnel safety or OK dilution. Research has been undertaken to outline a practical method in which the impact of blasting will be accounted for during the early excavation design stage by modelling, and during the following production stages by monitoring rock response to blasting operations.

Jan 1, 1994

By C Hunter, K Fedak, J P. Todoeschuck

"Perimeter wall control has a direct effect on the overall grade of any underground miningoperation. Mine management at INCO's Birchtree Mine in Thompson, Manitoba requiresmaximum perimeter wall control to meet high safety standards and to maximize nickel orerecovery. If footwall or hanging wall contacts are damaged by over_blasting, the ore maybe greatly diluted, mine productivity may be reduced and safety problems can arise.Excessive or poorly distributed explosive energy is a major cause of damage to the hostwall rock."

Jan 1, 1993

By J R. Brinkmann

The South African gold mining industry presently uses four different types of explosives in stope blasting. There is general agreement that the type of explosive has considerable effect on Important blasting results such as the degree of rock fragmentation, the intensity of damage to surrounding rock, and the success of break-out at the toe of the hole.

Jan 1, 1989

By Lawrence Cheng-Kwang Hu

"Since the only available delay detonator in Taiwan is electric delay detonator, which can beaccidentally initiated by fire, i impact force, friction, static electric, lighting, radiotransmitter, and stray current etc., that always represent fatal threatens to the blasting crew.Fire, impact, friction can be Prevented by handling carefully; lighting also can be detectedwith proper instruments. But when a blaster find an unknown extraneous current in his welllaid down blasting cable; what a horror scence will be expected especially the electricdetonators have been connected already."

Jan 1, 1993

By Andrew Drake, Mark Burchard, Peter Bellairs

The Astec Bluerock Quarry is excavating an extremely difficult to blast rock type due to its highly variable jointing density that leads to excessive oversize. A drill and blast benchmarking exercise led to eight recommendations to minimise this problem. Quarry personnel instigated a continuous improvement blasting program, that has implemented six out of eight recommendations, resulting in a large reduction in the oversize and increased crusher throughputs for a marginal 7% increase in drill and blast costs. Unit costs have reduced by an estimated 10%.

Jan 1, 1998

By Paul Worsey, Robert Sickler

Today, America's mining and construction industries are faced with operating under a condition of reduced profit margins. This makes the implementation of new technology far more sensitive to investment return than ever before. For this reason it is imperative that every effort be made to insure that new equipment and processes be designed to maximize their impact on improved quality, reduction in production cost and enhancement of safety. Using these principles as a foundation, a study was made to evaluate potential automation techniques for the blasting industry.

Jan 1, 1987

By Alex Jankovich, Darren Thornton, Sarrna Kanchibotla, Cam Grundstrom

The Porgera joint venture and Dyno Noble have commissioned a joint project to optimise the drill and blast operations to increase the overall profitability of the mine. One of the aims of this project is to increase the throughput of semi autogenous (sag) mill by optimising the blast fragmentation, The work done so far clearly indicates that significant improvements in sag mill throughput can be achieved by optimizing the blast fragmentation. This paper discusses the planning, implementation and results achieved so far in this project.

Jan 1, 2001

By Douglas Bartley, Kevin Hachmeister, Rich Barry

The use of explosive energy as a tool in mining and construction is the most effective way to move large amounts of rock that is otherwise unable to be efficiently excavated. Since the early days of explosive engineering utilizing black powder initiated by cap and fuse to the present day diversity of specialty products and technologies the goal has always been to "Break and Move" as much rock for the least expense possible. It has primarily been the competitive nature of our economy that has driven the advancement of technological innovations and practice. However, the concept of removing rock is not specific to the mining and construction industry. Since the dawn of creation, man has used rock as a medium to express his creativity in the form of sculpture. Even though the process of sculpture requires the removal of rock, the final work is defined by the rock that remains intact. This typically necessitates the extreme care of the sculptor to painstakingly chip away the rock allowing the image to emerge from the original mass of stone. The famous sculptor Michelangelo once said, "I saw an angel in the marble and carved until I set him free."

Jan 1, 2004

By Marlyn G. King, Robert L. Martin

Blasting activities in all four pits at Thunder Basin Coal's Black Thunder Mine are focused on cast blasting. With widths varying from 190 feet to 265 feet and bench heights varying from 90 feet to 175 feet, casting efficiencies vary with different geometry's. For example, the percent cast to final in the 200 foot pit is on the average higher than the 270 foot pit. The powder factors are somewhat higher in the narrower pits, thus increasing the cost of blasting. This leads to a very detailed look at the actual benefit of cast blasting and the associated cost of these benefits.

Jan 1, 1995

By Wang Xuguang, Kang Tingzhang, Zhang Xiaozhi, Wang Guoli, Li Ziqianga

Emulsion powder and granule explosive is produced through airflow fluidization technology by using W/O emulsion. Maintaining the microstructure of W/O emulsion, it has the advantages of both emulsion explosives, such as good water-resistance and detonation properties and powder explosives, such as low cost and east handling. The basic theory of emulsion powder and granular explosive, choices of constituents and formulation, technology for preparation, equipment and relevant parameters, product property as well as technology for safe use have been illustrated in this essay. Based on the above illustration, related factors influencing property and use result have been analyzed.

Jan 1, 2000

By P D. Katsabanis

Image analysis has been proposed to be an accurate and convenient means of measurement of blast fragmentation. The paper compares the results of image analysis to screening using laboratory scale rock piles. The muckpiles ranged from uniform distribution samples to well graded samples following the Rosin-Rammler distribution.Deviations between screened and imaged distributions were observed in most cases due to the loss of fines. Addition of fines in the system improved the result derived by image analysis considerably. It is suggested that techniques for the prediction of fines be evaluated for modifying the size distributions produced by image analysis.

Jan 1, 1999

By Guang-Xin Li, Rui-Ping Guo

Based on the analysis of factors affecting the cracking performance of Silently Cracking Agent (SCA), a new SCA structural model is built and a study on the swelling mechanism of SCA and a method to increase swelling thrust by adding the swelling agent are presented. The reason for blow-out and the theory for avoiding blow-out are put forward. The new model improves the SCA theory and provides new method for developing effective SCA. Based on experiments made in laboratory, two types of SCA are developed. A Temperature Control Meter (TCM) has been developed to solve the alltemperature- crack problem after studying the suitable temperature scope of SCA.

Jan 1, 2000

By S R. "Bob" Pilshaw

Productivity is the popular "buzz" word that catches the attention of most managers when it is featured in the more popular mining and construction magazines. Engineering Task Forces and teams are formed to take advantage of productivity opportunities in almost all phases of an operation except the drilling and blasting area.

Jan 1, 1988

By Jack C. Leader

The success of a blast using ANFO in wet boreholes is dependent on the quality of the bag the ANFO is packaged in. When a shot fails the dragline may stop and expensive redrilling may be necessary. The total loss to the mining operation can be hundreds-of-thousands-of-dollars.

Jan 1, 1981

By Jerry W. Schweiker

An extensive computer program has been developed which will store and analyze pertinent blast related parameters such as date, time, shot coordinates, charge, delay times, etc. In conjunction with these blast parameters, measured ground vibration information can be stored. In addition to actual seismograph data, predicted ground vibration in terms of velocity (inches/sec) can be generated for selected receiver locations. The magnitude of the blast generated ground vibration is based on scale distance relationships. The program can be used for planning blasts, to satisfy local environmental regulations and for insurance and/or legal purposes.

Jan 1, 1984

By Don Rapp, Rufus Flinchum

Air blast and flyrock are two of the most critical concerns facing the blaster of today. This paper will provide the blaster with proven procedures for recognizing open face and bench surface problems, explain various surveying methods, and provide the mathematical formulas for calculating and designing proper hole placement and explosive load configuration. A concept called "Pattern Footage" is utilized in conjunction with a USBM study to develop blast designs aimed at minimizing air blast and flyrock. In addition to this main focus, this concept can be used in shot displacement and cast blasting design.

Jan 1, 1993

By J J. Mullay, G W. Anderson, C J. McFinley, J F. VanNorman, C J. Kefer

Previous work has shown that testing of precompression effects conducted on a small scale under simulated field conditions in actual rock provides a reasonable model for the evaluation of explosives and initiators under the adverse conditions encountered in production blasting. Using this methodology can result in greater understanding of the phenomena as well as the ability to predict performance. This effort has been extended to evaluate various parameters not previously studied in a controlled fashion. The present paper describes the use of this technique to study the effects of delay timing on precompression effects. Intervals from 25 to 150 milliseconds are included in the study. Both VOD measurements and damage estimates are utilized in the evaluation. The results demonstrate that timing delay between holes is quite important in determining the overall effectiveness of a blasting program.

Jan 1, 1994

By Ron J. Elliott, David G. Otto

This project involved deep blast densification of recent volcanic avalanche debris deposits consisting of a 43 meter thickness of loose clean to slightly silty sand, gravel, cobbles and boulders deposited as a result of the 1980 eruption of Mt. St. Helens, Washington, U.S.A. This project was carried out to enhance the resistance to liquefaction or dynamic settlement of soil deposits under the bridge abutments for construction of the 59.4 meter long South Coldwater Creek Bridge. As this bridge is located close to the Mt. St. Helens fault, it will in all likelihood be subject to earthquakes in the order of 6.5 with expected accelerations of 0.55g. Without soil densification, the bridge would suffer severe structural damage in the event of a significant earthquake.

Jan 1, 1994

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

Several surface coal mining operations in North America are attempting to adapt microprocessor-based monitoring equipment as well as programmable logic controllers onto rotary blasthole drills, towards improving overall drill and blast productivity. These Monitoring While Drilling (MUD) systems permit the recording and processing of important drilling parameters such as rotary speed and torque, instantaneous penetration rate and weight on the bit, and enable the operator ultimately to optimize drill and bit performance. MWD systems on production drills in surface coal mines offer the potential to define mine bench geology in detail and in advance of explosives loading. Recent advance s in explosives and initiation technology will require such a detailed knowledge of ground conditions in order to be fully exploited. Additionally, the logic developed from drill monitoring technology will eventually enable full drill automation through feedback and control, once a more complete understanding of the influences of rock mass characteristics on machine performance is achieved.

Jan 1, 1988