The latter technique has become the most widely used in metal open pit mines, due to good results and its operational nature in hard rock formation. Basically, this technique consists of creating a continuous crack or presplit at a desired finished excavation line by initially firing a line of closely spaced, lightly loaded holes drilled there. Briere director, equipment marketing pangborn corporation, p. Delayed blasting tests to improve highwall stability a. Meanwhile in sweden, presplitting is a major part of the operation at the aitik mine with roc rigs doing the presplitting work and pit viper rigs taking care of the production hole drilling. Combining with stress concentration near circular hole in elastic. In this short 3 minute video by anthony konya, we will learn how to calculate burdens in both imperial and metric units.
A master plan of the presplit holes position at spacing of 1. Introduction presplit blasting is a technique used to reduce damage to excavation profiles during blasting by preforming a continuous fracture between parallel boreholes lightly charged with decoupled explosives along the line of the required surf. Here, 165 mm presplit holes are drilled at 20 degree angles on 33 m double benches. Presplit blasting presplit blasting is an effective technique for stabilizing the final wall in open pit metal mines. Pdf study on the raising technique using one blast based on the.
Dec 17, 2009 following are the techniques of controlled blasting. Sc08 education sequence comparison for metagenomics 1 introduction to blast powerpoint by ananth kalyanaraman school of electrical engineering and computer science. Where blasting is required, the blasting contractor will precede the construction crews, probing the pole. In this paper, a novel scheme based on artificial neural network ann method optimized by dimensionality reduction of factor analysis and mean impact value famiv is proposed to predict peak particle velocity ppv of blasting vibration. Shot blasting is used in almost every industry that uses metal, including aerospace, automotive, construction, foundry, shipbuilding, rail, and many others. The landbased segments of the necpl that may involve blasting include. The main objectives of presplitting in open pit mining are. After presplitting, the working resistance of supports was significantly reduced. Jul 24, 2015 this feature is not available right now.
Presplit charges must be fired simultaneously by joining all detonating cord. Blasting vibration is harmful to the nearby habitants and dwellings in diverse geotechnical engineering. Pdf theoretical calculation and numerical simulation were performed to. Precision presplitting is a widely used method of presplit blasting for the.
Evaluating and managing blasting risk page 1 evaluating and managing construction blasting risk by g. Abrasive blasting operations, engineering control and work. Presplit blasting spacing hole diameter x 12 burden 0. The dangerous goods safety explosives regulations 2007 explosives regulations require the preparation of a blast plan and written blast records before an explosive is used to blast rock or similar. Line drilling unloaded, cushion blasting smoothwall blasting presplitting 23 24. Ruby pipeline, llc plans to blast only in the areas where the rock cannot be economically excavated by conventional means. Pdf design of controlled blasting presplitting in golegohar iron. Pdf optimizing presplit blasting for environmental control. While representing owners at projects where explosives are used to excavate rock or demolish concrete, engineers participate in the management of blasting risk when they a design projects, b develop.
Deephole presplit blasting mechanism and its application. Types of blasting primary type of blasting will be for ditch excavation. Pdf design and application of blasting parameters for presplitting. Blasting will take place along the ruby pipeline project rightofway. Controlled blasting techniques are used to efficiently.
Design and application of blasting parameters for presplitting hard. Blast plan a written procedure that details the methods and manner by which a project blaster. Presplitting is the creation in solid rock of a fracture plane with pre determined direction and extent by the proper use of explosives and drill holes. The blasting crews ability to judge correctly the safe working line. Soundwall blasting met by the technique of presplitting, developed in the united states in the late 1950s.
This entry was posted in blasting, detonator, explosives, mining and tagged blast design, blast design formulas, blasting, explosives, mining. This reference may be obtained free of charge in adobe acrobat pdf format through the fhwa at the following. May 26, 2016 precision presplitting is being used in the blasting industry to increase safety and prevent overbreak in weaker rocks. The aesthetic aspect of a presplit should not bia judgment on the effi ciency of this technique, if sufficient can be with modified production blasts, the need for smoothwall blasting or presplitting can be reduced. Factors affecting shot blasting process factors affecting the shot blasting process initial condition of the component material and contamination velocity of abrasive size and shape of abrasive hardness of abrasive blast wheel location travel speed of part through the machine cycle time. Guide to blast plan preparation, including mining operations page 3 of 14. The mechanics of presplitting in discontinuous rock. Chapter 19 blast design introduction this chapter is an introduction to blasting techniques based primarily on the explosives and blasting procedures manual dick et al. This is especially true where specifications call for. Combining with stress concentration near circular hole.
While chambers in 1971 were being excavated in rock to fulfill a wide variety of functions, the main stimulus to their development had come from hydroelectricpowerplant requirements. Controlled blasting to control overbreak and to aid the stability of the remaining rock formation. Binary explosive a blasting explosive formed by the mixing of two plosophoric materials, for example, ammonium nitrate and nitromethane. Line drilling holes are spaced centre to centre two to four diameters apart but are more closely spaced at the corners. Preliminary tests on presplitting rock in the presence of an in situ static stress field were undertaken to study the influence of a horizontal static stress field on the creation of a vertical presplit fracture plane. This paper presents some blasting methods for achieving better final walls. Design and application of blasting parameters for presplitting hard roof with the aid of emptyhole effect article pdf available in shock and vibration 2018. Explosives, theory of breakage and blasting operations. It is anticipated that this may occur anywhere along the rightofway. The two areas that have the greatest impact on blast damage to the final wall are presplitting and trim blasting.
The mechanics of presplitting in discontinuous rock onepetro. Explanation for the program choices given in tables 3. Design of controlled blasting presplitting in golegohar iron ore mine, iran s. Controlled blasting for enhanced safety j in the underground. Blast basic local alignment search tool blast program selection guide table of content 1. Presplit blasting is a technique used to reduce damage to excavation profiles during blasting by preforming a continuous fracture between parallel boreholes lightly charged with decoupled explosives along the line of the required surface. Blasting that may be required for construction of substations will be achieved through blast detonation in delayed series that will result in no greater impact or vibration than those charges required for setting transmission line structures. Much of the following discussion on controlled blasting techniques has been. However, it is avoidable with the correct design and application of blasting at the final pit wall. Delayed blasting tests to improve highwall stabilitya progress report by virgil j. This manual was designed to provide a systematic approach to surface blast design.
Line drilling, trim cushion blasting, smooth contour or perimeter blasting, presplitting, selecting and employing various parameters of blast design, using modern technology, precise and accurate timing delays, muffle blasting at critical and congested areas. K, holmes and refined by others 2,3 consists of drilling a series of 2 to 3inchdiameter holes. Pdf design and application of blasting parameters for. Presplit blasting is commonly practiced in open pit mines to create shear planes on in situ rock slope to ensure pit wall stability, and also protect nearby structures against blast damage. This code applies to all workplaces covered by the whs act where abrasive blasting processes are carried out and where abrasive blasting products and equipment are used and stored. Presplitting is carried out in both transitional fig 2 and fresh rock fig 4, with trim blasting employed to further reduce the damage to the walls. When used for breaking hard rock, conventional blasting techniques can. Deephole presplit blasting technology was presented to avoid large area roof weighting. Surface effects are determined by media type, size, speed, and direction of impact. Merge blaster is the best ar toy ive ever tried cnet.
This indicates that sufficient gassing chemicals should be added to the gassed explosive blend during delivery so that an. Before firing the inner holes, the lightly charged perimeter holes are. Shotblasting is a method used to clean, strengthen peen or polish metal. There is a tendency to consider mine tunnels as temporary access ways, but how many mines are using tunnels that are thirty or. The mechanics of precision presplitting scholars mine missouri. A smooth blasting method in which cracks for the final contour are created by blasting prior to the drilling of the rest of the holes for the blast pattern. Normal production blast consists of detonation of 68 rows involving 140200 holes in a blast round. Welcome to academy blastings video on burden calculations for bench blasting applications. Line drilling is used mostly in small blasting operations and involves small holes in the range of 50 100 mm in diameter. The 115mm diameter holes are drilled over two benches 10m, with the top bench drilled at the design wall angle and the bottom bench drilled 5 degrees steeper to allow for drill mast access. Breakage diagram for presplit in jointed rock after worsey. Introduction the united states department of health, education, and welfares national institute for occupational safety and health niosh is responsible for conducting research and developing educational and training materials in the. Pilgrim pipeline project 3 appendix b blasting plan d. Though the basic concept originated in the united states, where the worlds first underground hydroplants.
Jan 07, 2018 merge blaster is the best ar toy ive ever tried. Limiting blastinduced damage on final pit walls aggnet. Presplitting is a controlled blasting technique with applications in open pit mines. The purpose of this blasting plan is to outline the steps that will be employed when conducting any blasting associated with tdinew englands tdine proposed new england clean power link project necpl. Typically the drilling program will be based on 1 row of 212 to 3 inch diameter holes drilled with a grid spacing of approximately 212 feet to 4 feet along the ditch line. Introduction to blasting blasting is the acceleration of particles by air or mechanical means to a surface or work piece to achieve a variety of physical effects. Results of presplit blasting for bench slopes with 140mm diameter boreholes. Deephole presplit blasting was successfully experimented for mining safely. Rock blasting and control overbreak fhwa us department of. Pdf this paper reports the further study carried out by the authors on the technique of longhole raising in one blast.
Presplit blasts are carried out in advance of trim blasting. Following are the techniques of controlled blasting. Lsdyna3d and discrete element analysis uncover the deephole presplit blasting mechanism for controlled roof caving. Underground excavations and structures rock chambers.
The merge 6dof blaster skips the goggles and goes for a gun. Dec 29, 2009 controlled blasting to control overbreak and to aid the stability of the remaining rock formation. This chapter is an introduction to blasting techniques based primarily on the. Blast plan preparation, including mining operations guide. The visual appearance of a blasted surface tends to be a dull to bright satinmatte finish. Limiting of overbreak with good perimeter blasting cautious blasting practices such as presplitting and smooth blasting are well known e. These tests indicated that it is easier to fracture the rock parallel to the. This means that one may have to use the blend in the entire hole. Factors affecting shot blasting process factors affecting the shot blasting process initial condition of the component material and contamination velocity of abrasive size and shape of abrasive hardness of abrasive blast wheel location travel speed of part through the machine cycle time exposure time. Blast pattern the plan view of the drill holes as laid out for blasting. Eb 15025 page 5 of 17 when site conditions and blasting procedures indicate that there is the potential for the migration and accumulation of gases, the contractor should specify information. Konya this is the first in a twopart article about precision presplitting.
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