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By Raj K. Rajamani, Solomon A. Tucker, Michael K. McCarter

"In a study aimed at exploring possible improvements in operating performance at an Open Pit Copper (OPC) mine in the western U.S., the impact of blast energy changes on crushing performance was evaluated. OPC feeds its 3-stage crushing plant in 12-hour-day shifts with skarn ore from three domains: Pit_B (B), Pit_S Low-Grade (SLG) and Pit_S High-Grade (SHG), in the blending ratio 1:1:1 (B/SLG/SHG). Thecrushed product is fed to a 2-stage ball mill circuit. "

Jan 1, 2017

By P A. Lang

Canada is constructing an Underground Research Laboratory as part of a comprehensive program to evaluate the concept of nuclear fuel waste disposal deep in stable rock formations. Careful blasting methods have been designed and quality control procedures have been used for the excavation of the access headings in the underground facilities. This paper describes the work done between 1984 December and 1986 December at the second level, 240 metres below surface.

Jan 1, 1987

By P S. Jaitawat, M Sarim, M P. Roy, P K. Singh, A Joshi

Mining is being carried out using the sublevel open stoping method at the Kayad underground mine. The mine will ultimately reach a depth of 390 m. Kayad village is only 100 m (horizontally) from the underground mining areas. As a result, blast-induced ground vibration is one of the major issues for the residents of the village. This paper deals with the process involved in optimising blast design parameters at the development face blast, slot raise blast and ring hole blast to control blast-induced vibration within safe limits while ensuring improved production, productivity and safety. In total, 1041 development face blasts, 110 slot raise blasts and 52 ring hole blasts were conducted, and 2612 vibration data were monitored in the village at different locations. Initially, electronic delay detonators were used, with an emphasis on controlling vibration in the surface structures. Subsequently, shock tube (Nonel) initiations were used as the blasting faces reached lower depths. A comparative study was also performed for both the initiation systems. The orebody width generally varied from 3.1 to 7 m, and ring hole designs were optimised accordingly. The number of holes in a ring was up to seven and the depth was up to 23 m, depending on the size/width of the orebody. The ring blasts were performed with 64–340 kg of emulsion cartridge explosive and detonated with explosive weight per delay of 10.92–17.16 kg. Extensive experiments were performed and blast-induced vibrations were controlled in the village. Deck blasting (ie up to four explosives decks) was used in a blasthole and the explosive charges were separated by delay detonators, which helped to control the vibration in the village. The actual detonation time of each deck was recorded by monitoring the in-hole velocity of detonation of the explosives, and the charging patterns were optimised accordingly to get the desired blast results.CITATION:Roy, M P, Singh, P K, Sarim, M, Jaitawat, P S and Joshi, A, 2015. Blast design and vibration control at Kayad lead-zinc underground mine, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 533–544 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

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 Terra Dinamica, Frank Lucca

This paper discusses blast design for vibration control in tight construction blasting. Topics include blast pattern geometry, blast design formulas, loading, explosives & initiation selection, and utilizing borehole deviation equipment and lasers, and rules of thumb. The paper will also explore vibration prediction, neighbor relations, and related topics, such as blast plan submittal. Various projects from metropolitan construction blasting operations will be used as examples. Examples include blasting in the inner city, next to pipelines, and in housing developments.

Jan 1, 2005

By G. R. Adhikari

Step 4: Selection of explosives and initiation system Various types of explosives are manufactured in India and a wide choice is available among them that include nitroglycerin based explosives, slurries, emulsions, ANFO (ammonium nitrate mixed with fuel oil) and heavy ANFO. The choice is also available between cartridged and bulk loading systems. In Indian mines, much importance is unduly given to the cost of explosives alone which is not conducive to optimization of blast design parameters. The concept of energy per meter of blasthole and the way in which the total explosive energy is partitioned between shock and heave is not considered in the prevailing practices. Besides, very little efforts are made to objectively evaluate the performance of explosives for a given site condition. Tailoring explosives is limited to changing the density of the bulk explosives. Cartridged explosives are still being extensively used in large operations where bulk explosives should be the preferred choice.

Jan 1, 2002

By P. Couceiro, J. Navarro

A new methodology to perform selective blast designs by adapting the explosive energy, hole by hole (or in the hole), to the rock properties as a combination of their strength properties through the X-Rock model has been developed based on drill-monitoring data from both autonomous and manual rotary drilling modes. For that, a thorough normalization process has been developed to minimize external influences in the data induced by the different rig system and the operator interventions during manual drilling operation. Principal component analysis has been used to combine drill monitoring information. Data from 48,385 blastholes, comprised in 102 production blasts at 7 different levels in one expansion of the mine have been used for the analysis. The methodology, called X-Energy, combines the X-Rock model outputs with actual blast design parameters (drill pattern, stemming and borehole length, explosive mass/density and others) and a constant variable obtained from a machine learning algorithm, to estimate size distribution and percentage of fines and coarse material, hole by hole, by combining and recalibrating the Kuznetsov (Cunningham, 1987) based equation. From it, a new shovel-independent diggability model has been developed as combination of the P80 size, the rock properties (from the X-Rock) and a constant variable obtained from a machine learning algorithm. The X-Energy application presented in this study have been implemented in Minera Escondida Limitada (MEL), to design and operate production blasts with the goal of varying the explosive density to the rock properties to obtain a more uniform size distribution and digging rates, hole by hole, based on a target size and rate, and improving slope care, preventing active faults to fail. The methodology has been applied and validated in 17 production blast (8,277 blasthole), unlocking an average of 12.8% reduction in explosives costs (explosive consumption), by combining a pattern expansion strategy and a better distribution of the explosive density within the blast. The results demonstrate how a better distribution of the explosive energy by varying its density in the hole according to the rock and blast geometry variables can reduce powder factor (explosive consumption) while improving or maintaining blasting and digging results.

Jan 1, 2024

By Michail G. Egorov

As well as destruction and moving rock, the blast energy sets up a seismic wave in the ground and a shock wave in the air, which can present danger to buildings and disturbance to human occupants. This shock air wave potentially can cause to destruction of a window glass, the window and door frames and partitions of buildings. In modern buildings, distinguished with high flexibility, the shock air wave can cause to the intensive wall vibration, dangerous for these buildings.

Jan 1, 1996

By Kavetsky A, Scott A

As well as breaking and moving rock, blast energy sets up a seismic wave in the ground which can cause significant damage to rock structures and buildings and disturbance to human occupants. This seismic ground vibration is potentially most damaging when its dominant frequency coincides with the resonant frequency of a structure, leading to high amplification factors between the input ground vibration and the resulting structural response. This paper outlines methods of identifying the resonant frequency of structures. It also describes a practical numerical method for the modification of blast designs to reduce the ground vibration energy in critical frequency ranges. The method is illustrated with two recent case studies.

Jan 1, 1990

By B Prasad, M P. Roy, P K. Singh, C Drebenstedt

Blasting operations play a pivotal role in the overall economics of opencast mines. The blasting subsystem affects all the other associated subsystems, ie loading, transport, crushing and milling operations. Fragmentation control through effective blast design and its effect on productivity is a challenging job for the practicing blasting engineer due to inadequate knowledge of actual explosive energy released in the borehole, effect of varying initiation practice in blast design and its effect on explosive energy release characteristic. This paper describes the result of a systematic study on the impact of blast design parameters on rock fragmentation at two mines in India. Both the mines use draglines and shovel-dumper combination for removal of overburden. Despite its pivotal role in controlling the overall economics of a mining operation, the expected blasting performance is often judged almost exclusively on the basis of poorly defined parameters such as powder factor and is often qualitative, which results in a very subjective assessment of blasting performance. Such an approach is a very poor substitute for accurate assessment of explosive and blasting performance. Forty-seven blasts were conducted with varying blast designs and charging patterns and their impact on the rock fragmentation are documented. A high-speed camera was deployed to record the detonation sequences of the blasts. The efficiency of the loading machines was also correlated with the mean fragment size obtained from the fragmentation analyses.CITATION:Singh, P K, Roy, M P, Drebenstedt, C and Prasad, B, 2015. Blast design parameters and their impact on rock fragmentation, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 755–762 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By M Higgins

Measurement while drilling (MWD) techniques can provide a useful tool to aid drill and blast engineers in open cut mining. By avoiding time consuming tasks such as scan-lines and rock sample collection for laboratory tests, MWD techniques can not only save time but also improve the reliability of the blast design by providing the drill and blast engineer with the information specially tailored for use. While most mines use a standard blast pattern and charge per blasthole, based on a single rock factor for the entire bench or blast region, information derived from the MWD parameters can improve the blast design by providing more accurate rock properties for each individual blasthole. From this, decisions can be made on the most appropriate type and amount of explosive charge to place in a per blasthole or to optimise the inter-hole timing detonation time of different decks and blastholes. Where real-time calculations are feasible, the system could extend the present blast design even be used to determine the placement of subsequent holes towards a more appropriate blasthole pattern design like asymmetrical blasting.

Jan 1, 2001

By Ricardo Gaviria, Vincinte Acosta

There are major blast design and field procedures differences between conventional blasting in horizontally bedded coal seams and blasting underneath coal seams in a multi seam deposit with seam inclinations of 14 degrees or more.

Jan 1, 1995

By Bruce Vandenberg, R. Frank Chiappetta, John Foley

Recent advances in solid-state, field portable, fast framing compact video camera systems and PC based frame capture hardware now allow blast imaging up to 1000 frames per second. Up to 4.1 seconds of data can be captured directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the MotionMeter system and compare these with the analogous aspects of film-based cameras and other systems. Of all blast monitoring systems and techniques available today, high-speed motion picture photography and videography still remain as the most valuable, stand alone, diagnostic techniques for troubleshooting and evaluating full scale blasts in the mining and explosives industries. High-speed image data, coupled with information obtained from other instrumentation systems, such as continuous velocity of detonation recorders, laser surveying systems, refraction and ground vibration recording seismographs, etc., can eliminate many assumptions about what actually took place in a blast. Thus, diagnostic confidence in evaluating both excellent and poorly designed blasts is increased, and optimum blast results, (which are application dependent), are achieved considerably faster when compared to the trial and error approach of relying on strictly the experience factor. Applications include developing site-specific blast designs, decay equations relating burden, burden velocity and explosive energy, determining ground response times, reducing coal damage, quantifying backbreak, evaluating the effectiveness of sternming, checking delay detonator firing times, evaluating air decks and for studying general dynamics. Motion analysis is performed with a 2D and 3D software package developed specifically for video analysis, but is also directly applicable to film analysis when using a digitizer. Dimensional controls, lens aberration, field set-ups and camera orientation are all automatically corrected for with matrix analysis.

Jan 1, 2000

By Bruce Vandenberg, Andy Bartfay-Szabo, Steve Conway

Recent advances in solid-state, field portable, fast framing video camera systems and PC based frame capture hardware now allow blast imaging up to 500 frames per second. Up to 8 seconds of data can be stored directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the SVClOOO system and compare these with the analogous aspects of film based cameras.

Jan 1, 1995

By Bruce Vandenberg, Andy Battfay, Don Lake, Steve Conway, Jeff Yorsz

"High-speed motion pictures are an invaluable resource for blasting analysis. Whether processed by the human eye or a computer, this imagery can provide important insight into a blast and its effects.While certainly popular, traditional high-speed film cameras hamper this process. Instant feedback is not available since film requires developing and, relevant in the case of automated analysis, film isnot immediately compatible with a computer. With these facts in mind, a new high-speed video camera system, the SVCSOO, has been developed. The SVC500 combines the capabilities of a high-speed film camera, the convenience of a solid-state digital video camcorder, and the computing power of a ‘486 PC to provide a complete, standalone platform for high-speed image acquisition and analysis. This paper will describe the design, features, and use of the SVCSOO andcompare these with the analogous aspects of film cameras."

Jan 1, 1994

By Cristian Rodriquez, Fernando Fernandez, Rodrigo Fuentealba, Tom BoBo, Maria Rocha, John Kemeny

This paper describes a case study that was conducted at a new mine in South America. This mine has significant geologic variations that will result in different distributions of hard and soft ore being mined at different periods of time over the mine life. A study was conducted to determine the optimum blast design that will meet the mill throughput requirement of 95,000 tonnes (104,720 tons) per day for the first 10 years of the mine life. As part of this study, field rock mass characterization and laboratory tests were conducted. This includes standard rock mechanics tests as well as rock breakage tests used in mill simulations. The geology of the ore body was broken up into four Geologic Units, and statistical variations in the properties were determined for each unit. Using this data along with the data on the occurrence of the different geologic units over time, simulations were made of the run-of-mine (ROM) fragmentation due to different blast designs, and these results were used in simulating the resulting throughput after crushing and grinding. Four blast designs were considered with powder factors of 0.44, 0.54, 0.64 and 0.94 kg/t. The results of this study show that determining the proper blast design is important in ensuring that the mill throughput requirement will be met over the mine life.

Jan 1, 2015

This presentation is a 20 minute snippet of my professional career, and my progression in the mining industry, from a lazy uni student to an up-and-coming blast engineer in the middle of a mining boom.My name is Daniel Hepburn and I am a blasting engineer for Orica Mining Services. I graduated from Royal Melbourne Institute of Technology (RMIT), in Melbourne in 2003. I completed both of my final year projects with Orica Quarry Services and was offered an assistant shotfiring job, which I accepted and worked for eight months. Having missed the cut-off date for the Orica graduate program, I planned to work with Quarry Services until the following year where I hoped my marks and the experiences I had gained would secure a graduate position. I didnÆt have to wait long, as in August of that year, I was offered (and I accepted) a graduate position in Perth as a technical services engineer for Orica Mining Services. The Orica graduate program is based over two years, and consists of real roles from day one; however, there is also opportunity to fast track the program for high performers. There is a structured rotation, from site to site, interstate or even international if you are so inclined. This includes the backpacker program, which allows graduates to experience the Orica culture in countries of their choice. There are also opportunities to try cross-functional roles in the different Market segments within Orica. I was lucky in that I knew what I wanted to do and where I wanted to work, so I stayed in Perth for my entire graduate program. I was also lucky enough to be fast tracked and finished my graduate program in 15 months. At the end of 2005 I accepted a position as an open cut blasting engineer based in Perth and even in such a short period of time I have already completed a number of major accomplishments. Some of these accomplishments are described below. This paper is available as a PowerPoint presentation only.

Jan 1, 2006

By D La Rosa, K Caron, H Mamani, W Valery, R Diaz

The Gold Fields Cerro Corona copper-gold deposit in Peru has heterogeneous rock characteristics in terms of its mineralogical, geological and geotechnical properties. Blast design variations in these conditions directly impact the run-of-mine (ROM) fragmentation, which in turn influences downstream process efficiencies. In particular, when harder ore is processed, throughput and circuit performance may be limited.To evaluate the potential to increase throughput and improve overall plant performance by optimising blasting practices and comminution circuit operation, Gold Fields La Cima engaged Metso Process Technology and Innovation (PTI) to conduct a full process integration and optimisation project at Cerro Corona. Blasting, crushing and grinding processes were reviewed to identify the potential to achieve substantial improvements in productivity when treating the most competent ore types.Site-specific models of the blasting, crushing and milling processes were developed using SmartTagTM ore tracking technology for calibration and validation. Ore tracking permitted locations in the blast volume to be queried against the geotechnical block model to determine the hardness and structural parameters of the feed to the comminution circuit. They also ensured surveys were conducted when ore from the audit blast was flowing through the crushing and grinding circuits.The predictive models developed enabled PTI to demonstrate how changes in blast design influenced both ROM fragmentation and the performance of downstream comminution processes. Outcomes of the project suggested changes to blast designs and comminution practices, and these were partially implemented for a validation trial. The trial demonstrated a 14.8 per cent increase in mill throughput for the specific ore selected for the study, and an average increase of 5.7 per cent for all ore types. There is potential to further increase throughput and process performance if all recommendations are implemented. This paper describes the methodology used and benefits to the operation from the mine to plant.CITATION:La Rosa, D, Caron, K, Valery, W, Diaz, R and Mamani, H, 2015. Blast fragmentation impacts on downstream processing at Goldfields Cerro Corona, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 333–342 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By M J. Thurley, M Wimmer

To assess the present-day functionality of large-scale sublevel caving at LKAB Kiruna a comprehensive measurement program was undertaken involving blast function, fragmentation and gravity flow. As part of this assessment, a fragmentation measurement trial was performed based on 3D imaging of the drawpoint and corresponding bucket load of the underground load-haul-dump (LHD) excavator. 3D image data from stereo photogrammetry was collected and an automated image analysis strategy developed. A number of data sets were collected for each of the drawpoint and LHD bucket, along with sieving results for four of the LHD bucket loads (totally about 70 t). Two of the sieving results were used to inform the automated image analysis strategy, and two were held back as a comparison. Large variations in the visible particles are apparent when comparing corresponding drawpoints and LHD buckets highlighting the impact of sampling location and the need to measure large quantities of data in order to avoid bias from small samples. The results show that 3D imaging and analysis can produce fully automated measurement and analysis of the visible particle size distribution. Although this is not the same as the sieve-size distribution it provides useful estimation of both the larger size classes and a bulk estimate of fine material below approximately 60 mm. The 3D stereo photogrammetry measurement system used produced very high 3D point density but this was achieved using a custom up-sampling technique which significantly smoothed the data, removing small particles, smoothing edges, and this negatively affected the particle delineation algorithms.CITATION:Thurley, M J, Wimmer, M and Nordqvist, A, 2015. Blast fragmentation measurement based on three-dimensional imaging in sublevel caving drawpoints and underground excavator buckets at LKAB Kiruna, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 763–774 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By A. Ribeiro

The effective utilization of resources and process optimization play a crucial role in the sustaining and growth of overall businesses. This principle holds true in the mining sector, where particular attention is required during the comminution steps. This necessity arises from the fact that mining operations often consume substantial amounts of energy in mineral processing. Therefore, it becomes imperative to thoroughly study the integration of comminution steps. In many instances, an approach to be studied is the operation commencing with the drill and blast phase and culminating in the grinding product process. Nevertheless, establishing an optimal integration between drill and blast operations and the grinding phase is a complex undertaking due to the direct influence of rock characteristics on this process. And in many cases, the complexity and variability of such physical characteristics makes mining operations to ignore such influence. Consequently, Enaex Mining Technical Solutions (EMTS), in collaboration with Lundin Mining's Chapada Mine engineering team, and with the assistance of Hatch Consulting and Technology, has undertaken a comprehensive study aimed at enhancing mill throughput at the Chapada operation. The basis of this study lies in characterizing the rock masses present in the Chapada Mine to gain a deep understanding of the material that needs to be comminuted. Subsequently, the mineral processing team determined the most suitable size distribution for the Run-of-Mine (ROM) material. With this information, the drilling and blasting team built a site-specific blast fragmentation model, able to simulate various blast design scenarios. This approach enabled to optimize the utilization of available drilling and blasting resources while striving to achieve the optimum ROM characteristics. Since 2021, the Mine to Mill methodology has been progressively implemented at the Chapada Mine. As a result, the blasting engineering team now utilizes the blast plans generated by the fragmentation model simulations as a foundation for designing blast plans that align with the operational and financial capacities of the mine. Overall, it was predicted that this implementation could lead to an average increase in mill throughput of 13-22 % depending on blend feed, once all recommendations are implemented. Even with partial implementation, plant results demonstrate a 5 % increase compared to the period before the Mineto-Mill project, without any coarsening of the associated grinding product size.

Jan 1, 2024