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By Thomas L. Barkley

My historic auditing of Underground Drilling and Blasting Practices has demonstrated to the author the need for reviews of many mines' procedures in these processes. Poor understanding of the basic principles and practices of the drilling and blasting science in Underground Development Mining has created significant costs to mining operations in many instances.

Jan 1, 2019

By Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Mehmet Aksoy, Deniz Adiguzel

The environmental problems arising from ground vibration has been faced and discussed frequently in various industries such as quarry, mining, civil works, shaft, tunneling, pipe line and dam construction etc. where the blasting operations are unavoidable. In bench blast design, not only the technical and economical aspects, such as block size, uniformity and cost, but also the elimination of environmental problems resulting from ground vibration and air blast should be taken into consideration. The prediction of ground vibration components plays an important role in the minimization of the environmental complaints. This paper presents the results of ground vibration measurements carried out in the quarries located on the different sides of Çatalca district in Turkey. In order to predict peak particle velocity level for this district, ground vibration components were measured for shots during bench blasting at these quarries. In blasting operations; ANFO is commonly used as blasting agent at the quarries. The type of priming and firing differed from quarry to quarry. The parameters of scaled distance (charge quantity per delay and the distance between the source and the station) were recorded carefully and the ground vibration components were measured for all blast events by using different type vibration monitors. The absolute distances between shot points and monitor stations were determined by using GPS. The equation of square root scaled distance extensively used in the literature was taken into consideration for the prediction of peak particle velocity. In order to predict, and compare the influence grades to the neighboring buildings, and structures at the Çatalca district, the particle velocities and frequency values of all blast events are evaluated according to the United States Bureau of Mines (USBM) and German DIN 4150 Norms due to the lack of a national standard in Turkey. Then, the data pairs belonging to these quarries were gathered together to represent the district and were analyzed statistically. At the end of statistical evaluation of the data pairs, an empirical relation which gives average line at 95% confidence level and upper bound 95% prediction line with a reasonable correlation coefficient was established between peak particle velocity and scaled distance

Jan 1, 2007

By Joel Warneke, Cristian Caceres, Ed Mchugh

NIOSH researchers collected basic data from two blast rounds at the SSX-Steer Mine as a component of a larger study on controlled blasting, the goal of which is to reduce injuries from falling rocks in underground mines. Drilling and blasting procedures at the mine were observed. Rock mass property data were collected, a program of seismic monitoring and analysis was conducted, and 3-D laser survey scans of the workings before and after each blast were performed. The geologic data showed that the rock mass quality was characterized as poor to very poor. It was essentially uniform within the panels examined. The recorded seismic data indicated that fill material acted as an effective damper to seismic energy. The pre- and post-blast laser scans showed both over-break and under-break conditions, highlighting the problems associated with blasting a weak rock mass. By comparing the achieved results to the intended design, potential improvements in the drilling and blasting practices can be identified. Comparison of these data with similar data from other mines will help define how various combinations of rock and fill behave during blasting. Through studies such as these, data collection procedures and analysis techniques can be refined. An ultimate goal is to develop blast procedures tied to rock mass characteristics that can minimize damage to rock in the perimeter of the opening, limiting the amount of loose rock and improving the safety of miners.

Jan 1, 2008

By H. S. Venkatesh R. Balachander, G. C. Naveen

During the construction of a 1020 MW underground hydroelectric project in Bhutan a huge rock fall took place in the Downstream Surge Chamber (DSC) during March 2016. The total quantity of rock in the fall area is estimated to be about 1,50,000m3 (2.6 billion cubic feet), out of which about 25,000m3 (0.44 billion cubic feet) of muck was removed. The removal of muck was stopped apprehending that the cavity formed due to the rock fall may get further aggravated leading to widening and destabilising the adjacent transformer hall cavern or it might day light as the top cover was about 190m (623 feet). As the fall has virtually blocked the 314m (1030 feet) long cavern and divided it into two different chambers (south and north), and that the muck cannot be disturbed, it was decided to erect concrete wall on either side of the fall up to the cavern roof and then later address the filling of the cavity with appropriate fill material. As the access to the DSC was there for the southern side it was decided to extend a cable tunnel which was terminated at a distance on the north side of the cavern by D&B so that once it gets punctured into the north wall of the DSC it can be used to access the fall from this front too. This is a unique situation where in every blast approaching the DSC, the parting between them is diminishing and hence the tunnel blast will be exerting axial load on the parting wall leading to dynamic transient loading conditions and buckling may take place on the northern wall of DSC. This paper describes the various drill blast combinations adopted for successful excavation of this tunnel.

Jan 1, 2019

By Wayne Rogers, Sarma Kanchibotla, Alan Tordoir, Bryon Bisiauz, Seth Ako, Eric Engmann

Blast induced rock mass displacement can have a significant impact on ore loss & dilution. The mischaracterization of the grade boundaries both prior to, as well as a result of blasting can lead to significant financial losses on account of ore loss and dilution. Ore dilution occurs when waste material is miscategorised as ore and sent for processing diluting the run of mine head grade and recovery. Ore loss takes place when valuable mineral is miscategorised as waste and sent to the waste dumps, thus never being processed and recovered.

Jan 1, 2012

By Clara Godoy, Álvaro Dapía, Paulo Couceiro, Håkan Schunnesson, Juan Navarro

This paper applies geostatistical tools in Measure While Drilling (MWD)data to estimate the probability distribution of values in all the points of the studied domain in order to assess the continuity of rock classes between boreholes. The analyses carried out by Ghosh et al.(2018) and Navarro et al.(2019) have been used as starting point of this work to classify the geotechnical rock condition in four classes: solid rock, fractured rock, cave-in rock and cavity. From it, an application for the geotechnical rock condition of ore bodies have been developed, aiming at characterizing the rock before the charging the holes to minimize unexpected rock conditions and to address issues associated with charging and blasting operations. Such problems are closely related with non-optimal rock fragmentation after blasting. The procedure has been applied in the geotechnical block model results obtained from Navarro et al.(2019)’s work in the Luossavaara-Kiirunavaara AB’s (LKAB) Malmberget underground iron ore mine, Sweden. Navarro et al.(2019)’s model was developed based on102 fan-holes from five ore bodies and extrapolated to the full-scale in20 drifts with 5600 fan-holes from two orebodies. A multi-step transformation of the MWD parameters was carried out in order to minimize external influences other than the rock mass. The study shows the calculations of the variogram and kriging estimation in the 3D domain for six ring-blasts, from one of the ore bodies studied in Navarro et al. (2019)’s work to assess the continuity of the rock classes along the six ring-blasts in a 3D mapping model. For that, intermediate rings between the measured ones from the MWD have been estimated. The probability distribution of values in the entire domain of rings with measured samples has been plotted together with the rock classes identified by the blasthole paths. The results show high accuracy in the matching between the kriging and the values given by the MWD data, allowing to visualize smooth trends of different rock classes along the ring. The representation of the 3D mapping model for the six ring-blast shows clear fractured and cave-in zones developed along the drift that correspond to zones with geotechnical problems found, as from internal reports.

By Ruilin Yang

The vector sum peak particle velocity (PPV) of blast vibrations describes the blast vibration intensity more completely than the PPV of a single component waveform. It is more logical to use a vector sum PPV as a vibration limit than using a single component PPV. In 1980 the USBM recommended the frequency related peak particle velocity criterion. So far this method has been only applied to single component waveforms, but not to the vector sum PPV since there is no method available to associate a frequency to the vector sum PPV. The present paper describes a method to define a principal frequency associated with vector sum PPV. The method is based on the weighted average of the principal (zero-crossing) frequencies of the three tri-axial components at the time of the PPV.

Jan 1, 2015

By Kwang-Yeom Kim, Dong-Gyou Kim, Hyo-Kwan Yoon

This study was intended to simulate the blasting model using notched-hole with numerical approach. Numerical analysis approach was applied to compare and evaluate the blasting model using notched-hole and circular hole. To implement non-linear dynamic blasting model, blasting analysis was carried out with AUTODYN code. Behavior of two models was compared and evaluated using AUTODYN and visual analysis and quantitative evaluation based on pressure and stress to verify the effect to induce the destruction territory to the specific direction when blasting with notched hole was attempted.

Jan 1, 2010

By Bonifacio Digay

Stawell Gold Mines (SGM) is an underground mining operation located in Victoria, Australia.The mining method employed is long hole retreat stoping, utilising up and downholes and artificial concrete pillars. Stawell is currently mining the Golden Gift and Magdala orebodies.

Jan 1, 2012

By Joseph Indeck, Seokbin Lim, Andrew Thompson

In the design of explosively driven penetration devices, understanding the impact conditions between the explosively propelled penetrator and the target is one of the most important steps in optimizing the performance of the device. These impact conditions are especially prevalent when a shaped charge jet impacts concrete, which is not an ideal target material. The specific impact conditions, including but not limited to the impact angle and jet properties, create a great deal of variability that affects the performance and penetration of the shaped charge. The large amount of impurities and voids in concrete, along with its heterogeneous nature and the general strength characteristics, make concrete a non-ideal material for shaped charge jet penetration. These material characteristics lead to a highly non-linear deformation behavior of the concrete target during a hyper-velocity impact.

Jan 1, 2011

By T. Szendrei, S. Tose

This paper will review several flyrock incidents that occurred recently in the South African mining industry to highlight that potential difficulties of the historical approaches to the problem of flyrock based on correlation studies and regression analysis, including artificial neural networks and similar techniques. These process are not capable of addressing two core issues – root causes of flyrock and projection velocity. A further shortcoming of correlation techniques is that they give no information on the influence of rock size and shape on the flight distance. The scaled depth of burial model for crater blasting in the collar zone and bench face does not specifically address the question of flyrock velocity. A third approach, based on flight trajectory calculations, often neglects the very significant effects of air resistance on the trajectory. Some trajectory models incorporate air resistance but use an implausible fragment velocity model that cannot propel sizeable rocks to distances much beyond 150 m. (Approximately 500 ft.) Nonetheless, trajectory calculation incorporating the effects of air drag affords the most promising approach to the prediction of flyrock range. A unique and insightful feature of the proposed realistic flight modelling is that it collapses all suspected causes of flyrock, many of which are not well understood, to just a single parameter – the launch velocity. This indicates that the root causes of flyrock lie in the mechanisms of momentum transfer to broken rock and suggests new avenues of study for the explosives industry. In this paper we use the trajectory model to identify certain conditions on the bench whereby the impulse of gas pressure acting on fractured material on or close to a free face is enhanced, resulting in a greater transfer of momentum to potential flyrocks.

Jan 1, 2024

By A T. Spathis, J J. Felice, W Klass

Cast blasting has become one of the most efficient ways to move waste rock in open cut coal mining. It is used at Mount Thorley Mine in conjunction with a dragline to move some of the overburden onto the spoil dump.

Jan 1, 1992

By James Ludwiczak

We are coming to an end of an era in Midwest surface coal mining. For many years, large tracts of coal lands were readily available for sale or lease to surface mine operators.

Jan 1, 1980

By Oldrich Machacek, Gary R. Eck

The underwater detonation test method has been long recognized as a useful tool for the evaluation of the energy release and relative effectiveness of commercial explosives. In this study, underwater energy tests were performed for emulsion and watergel commercial explosives in comparison with ANFO. Heavy ANFO type blends based on emulsions and watergels were also investigated under and without confinement.

Jan 1, 1990

By Walter Jr Duke

The security of explosive materials is a vital concern to every mine, quarry and contractor engaged in blasting. Proper construction of magazines and sufficient locking mechanisms are the fundamental means of maintaining secure storage. The object of this paper is to review the proper methods of construction of storage facilities for explosives as defined by the Alcohol, Tobacco, and Firearms regulations. Subpart K subsection 55.208 and the Institute of Makers of Explosives recommendations.

Jan 1, 1991

By Jaki M. Wilson, Neville T. Moxon

The detonation pressure of ANFO can be significantly reduced by the addition of low density materials such as polystyrene, bagasse, sawdust or perlite. Laboratory and field test results have shown that homogeneous mixtures of these low density explosives can be produced in a bowl truck and loaded into a blasthole without segregation. The detonation pressure of the mixture can be altered to be more compatible with the material in which it is being used by varying the quantity of low density additive incorporated into the mixture. Field results have shown that these low density explosives can lead to significant cost savings without compromising fragmentation or production.

Jan 1, 1989

By John M. Bolger, Keith E. McMaster

Excessive salt fines are undesirable in underground salt mining as they are considered a costly waste by-product. This paper describes an extensive explosive application program conducted at The Canadian Salt Company Ltd, located in Pugwash, Nova Scotia, Canada. The prime objective of the program was to reduce the quantity of fines generated from this company's underground production blasts. The program was known as the "The Fines Reduction Program".

Jan 1, 1996

By Y Omura

If dynamite is used in hot metal mines, it may be subject to decomposition, and the increase in nitroglycol vapour under the high temperatures causes bad headaches of workers. Also the explosives containing ammonium nitrate are very dangerous when mixed with sulfide ores at a high temperature!. Therefore we developed a heat-resistant water gel explosive which is safe to be handled at these hot metal mines.

Jan 1, 1983

By W. J. Birch

The recording of information is critical to the blasting process, whether it be for planning purposes, statutory requirements or environmental compliance. The review and analysis of past data can play a key part in a blast.s design. Statutory records must be held to preserve operational licenses and well-maintained monitoring records are a vital defence for today.s litigious society. However a single blasting event can be responsible for generating vast amounts of data. This information maybe collected pre or post-blast and in their individual ways may have a requirement to be logged, processed, analysed, reviewed and reported before eventually being archived.

Jan 1, 2002

By M Siefert, P Moser, T Oberndorfer

"The EC-project ""Blasting Control"" with partners from France, Austria, Italy and Greece dealt with the development of a diagnosis system, which enables blasting experts to investigate in detail on probable reasons of poor blasting results in underground drifting. The system incorporates monitoring of geometric, explosive, vibration and granulometry data. All data are compiled in a database and are provided for direct retrievement by demand of the experts in a graphical environment. This paper focuses on the advantages of such graphical system for both research tasks and applications in real testing situations. It describes the procedure of monitoring and presents a selection of graphical outputs generated during data processing immediately after blasting. Benefits of detailed monitoring in respect of detecting sources of errors are explicated by a actual example of a test series in a mine. The paper will conclude with an outlook onto the scientificresearch work which is planned to be based on the results of hitherto investigations."

Jan 1, 1996