This paper reports the further study carried out by the authors on the technique of longhole raising in one blast. Limiting of overbreak with good perimeter blasting cautious blasting practices such as presplitting and smooth blasting are well known e. The entire r must be init recommenc always be fc it is essentia safe, reliable and user friendly. Kg of explosive per meter of column for given density gcm. The fumes generated during blasting operations, especially during trenching operations, can migrate and collect. Line drilling holes are spaced centre to centre two to four diameters apart but are more closely spaced at the corners. There is a tendency to consider mine tunnels as temporary access ways, but how many mines are using tunnels that are thirty or. Introduction rex minerals limited plans to develop and operate the hillside mine, situated 12 kilometres south of the. The crack helps to screen the surroundings from ground vibrations during the firing of the main round. Presplit blasting involves drilling a single row of holes along the back of the final excavation zone.
It is practiced most often in mining, quarrying and civil engineering such as dam, tunnel or road construction. A study was conducted to evaluate the effect of air deck pipe deck, water deck technique to control induced ground vibration in production blasting and presplitting at tata west bokaro, colliery. These solutions take internet faxing to the next level, empowering employees to batchsend missioncritical documents like invoices, quotes, and marketing material with. Bender 1999 defined production blasting as the type of blasting that is designed to fragment a predetermined volume of rock. This site is like a library, you could find million book here by using search box in the widget. Comparison of presplit and smooth blasting methods for excavation. Golegohar iron ore mine is located in southern iran. During the process of blast casting in surface coal mining, presplitting is always detonated earlier than the major casting holes. Controlled blasting for enhanced safety j in the underground. Explotech cushion blasting this blasting method is very similar to presplitti two methods are often considered identical.
Total explosives in the blastvolume of rock blasted for. Alegra has been applied to a 2d simulation of presplitting using decoupled explosives in rock blasting with very interesting results. Study on the raising technique using one blast based on the. Assessment and application of a singlecharge blast test. The mine was using digishot detonators and signature hole analysis timings to control vibration so any presplit holes tied into a production blast would have to be timed in this manner. Design of controlled blasting presplitting in golegohar iron ore mine. Explotech presplitting preshear, smooth blastin a technique designed to provide the best possible p the final excavation wall row of presplit holes are drilled at reduced spacing burden presplit row may be fired days in advance of drillin blasting the production holes or at least 200 ms pri production holes in the same blast holes are loaded with decoupled charges presplit holes are detonated. Though the basic concept originated in the united states, where the worlds first underground hydroplants. 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. Face of rock 1 face of overburden 1 variable overburden top of rock rock 5 5 minimum r. Explotech presplit rules of thumb hole diam in charge wt lbft. The study was aimed at optimization of blast parameters to enhance over all blasting efficiency in quarry by using explosive. The spacing is kept closer than buffer holes and production holes.
The mechanics of presplitting in discontinuous rock. Our pdfblaster, clickfax and actiondocs products allow businesses to send and receive faxes and email over the internet without the need for expensive and hassleprone hardware. Lets say you have a list of people and you are sending a. An ideal blast results in a minimum of damage to the host rock with minimum of overbreak. Jul 24, 2015 this feature is not available right now.
Use o dyno noel blast design digishot detonators and. Presplit blasting spacing hole diameter x 12 burden 0. Blasting, primarily trench and ditch blasting, can displace rock and damage adjacent pavement and underground utilities. Governments official website for the office of surface mining reclamation and enforcement osmre. The landbased segments of the necpl that may involve blasting include. 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. Once the crack is made, it screens off the surroundings to some extent from ground vibrations in the main round. To understand differences of smooth and presplit blasting for the excavation of rock wells, two field experiments using these two techniques are. Design of controlled blasting presplitting in golegohar iron ore mine, iran. If desired, the contractor may verify the accuracy of the model by field surveys.
Ale codes can also treat explosive detonation and the expansion of the explosive. A master plan of the presplit holes position at spacing of 1. Presplitting has the main effects on defining blast casting boundary, decreasing the blasting vibration and effects on the fixed slope, and enhancing water drainage. This reference may be obtained free of charge in adobe acrobat pdf format through the fhwa at the following. Development and application of blast casting technique in. A new perimeter control blast design concept for underground metalnonmetal drifting applications stephen r. Arbitrary lagrangian eulerian ale computational techniques allow treatment of gases, liq uids, and solids in the same simulation. Import an asdrilled pattern from csv or drl file and compare with the design to make sure all blastholes are drilled within a specified tolerance of the design blastholes, and. Initiations and timing effects as well as patterns are also discussed. Hillside copper mine blast management plan program for environmental protection and rehabilitation pepr 7 1. Smooth blasting is a type of controlled blasting thats done either before production blasting, as an alternative to presplitting, or afterwards, either as an entirely different event or as the last delay of the production blast. Dec 17, 2009 following are the techniques of controlled blasting.
Drilling and blasting is the controlled use of explosives and other methods such as gas pressure blasting pyrotechnics, to break rock for excavation. As a rule, if the presplit holes are to be detonated with production blast holes. 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. Design of controlled blasting presplitting in golegohar iron ore. Create reports showing pattern layout, graphic pdf maps of the design with labels and transparent textures in 3d. Balasubramanian centre for advanced studies in earth science university of mysore mysore6 2. 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. When used for breaking hard rock, conventional blasting techniques.
A new perimeter control blast design concept for underground. Shock and vibration hindawi publishing corporation. Study on the raising technique using one blast based on. Presplitting and production blasting of rock slope cuts. Technical inormation product disclaimer dyno nobel inc. The visual appearance of a blasted surface tends to be a dull to bright satinmatte finish. All books are in clear copy here, and all files are secure so dont worry about it. Using presplitting method excavation in rock 1o 35 maximum 35 maximum 1 width berm rock width berm 1o min. The detonation of the explosive at the bottom of the hole sends a shock wave up the borehole driven by the explosive gas expanding into air. Controlled blasting techniques include presplitting, cushion blasting, and sliver cut blasting. Computer generated road design data files in the format of the approved software containing the ground model may be supplied to the contractor, as advised prior to commencement of the contract. Underground excavations and structures rock chambers.
Box 380, hagerstown, md 21740 n recent years, shot blast cleaning systems have replaced other mechanical or chemi cal metal surface preparation processes. Johnson department of health and human services centers for d isease control and prevention national institute for occupational safety and health. You are all aware that mining is a major economic sector of any country. 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. Modeling explosiverock interaction during presplitting. The major effects of presplitting include defining the blast casting boundary, decreasing the blasting vibration, enhancing water drainage, and maintaining the stability on a fixed slope. Explotech presplit rules of thumb hole diam in charge wt. The mechanics of presplitting in discontinuous rock onepetro. Pdfblaster ecommerce products and services, internet faxing. 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. Osmres business practices are to reclaim abandoned mine lands title iv, regulate active coal mines title v, and apply sound science through technology transfer.
Presplit blasting, or presplitting, is used before production blasting to protect the final rock face from damage caused by the production blasting. Presplitting creates a fracture plane along the final slope face, which prevents the radial cracks created by production blasting from penetrating into the finished face. 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. Blast plan a written procedure that details the methods and manner by which a. The main objectives of presplitting in open pit mining are find, read. Soundwall blasting met by the technique of presplitting, developed in the united states in the late 1950s. Presplit blasts are carried out in advance of trim blasting. Suggestions are offered for handling such problems so as to. Line drilling is used mostly in small blasting operations and involves small holes in the range of 50 100 mm in diameter. 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. 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. Noxious fumes blasting generates carbon monoxide and other noxious fumes.
Understanding the connection between blasting and highwall stability. Please click button to get presplitting a controlled blasting technique for rock cuts book now. Pre splitting in open pit mining is performed by arranging a row of blasting holes behind the main blast pattern. Section 2xx blasting for rock cut slope excavation 2xx. Blast plan a written procedure that details the methods and manner by which a project blaster. Design and application of blasting parameters for presplitting hard. Explotech buffer blasting often used in conjunction with other controlled techniq such as presplitting hole diameter and depth is generally the same as produ holes spacing is generally 0. Surface effects are determined by media type, size, speed, and direction of impact. Pdf presplitting is a controlled blasting technique with applications in open pit mines.
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. The proposed blasting plan shall show the location of shots. Ale methods include the ability to treat shockwaves in gases, liquids, and solids and the interaction of shockwaves with each other and with media from one of the other categories. Abrasive blasting operations, engineering control and work. Blast hole pattern parameters acts as a key role in blast casting effect, on both smaller and oversized row, and hole distance will result in poor casting and breaking effect.
Table 5 shows recommended borehole diameters, burden, spacing, and explosive charges for smooth blasting. Briere director, equipment marketing pangborn corporation, p. Blast pattern the plan view of the drill holes as laid out for blasting. Section 2xxblasting for rock cut slope excavation 2xx.
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. Email blasting a pdf very few email service providers provide the ability to attach a pdf file or other file attachments. Blasting awareness free download as powerpoint presentation. Modeling explosiverock interaction during presplitting using. Office of surface mining reclamation and enforcement osmre. Binary explosive a blasting explosive formed by the mixing of two plosophoric materials, for example, ammonium nitrate and nitromethane. The most commonly used of these techniques is presplitting. Pdf optimizing presplit blasting for environmental control and pit. 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. The project is using surface and underground blasting to excavate. Design of controlled blasting presplitting in golegohar iron ore mine, iran s.
In other words, the entire length hole is filled with sand or crushed stone. 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. However, conventional presplit blasting often results in high blastinduced ground vibrations and airblast in nearby communities of the adamus. Cushion blasting is only possible where vertical are drilled. This is especially true where specifications call for. Perimeter or contour holes are drilled along specified final excavation limits and are lightly loaded than that of buffer holes and production holes. Since the presplit holes would have to be fired first, behind a row or two of production holes, the blast. Presplit blasting presplit blasting is an effective technique for stabilizing the final wall in open pit metal mines. Line drilling holes are spaced centre to centre two to four diameters apart. Normal production blast consists of detonation of 68 rows involving 140200 holes in a blast round. Study on air, water deck in presplitting and rock blasting. In the previous work reporting the results of preliminary study, method of vertical crater retreat vcr multipledeck shots with different and smaller slice heights was used to excavate the raise in one blast. These tests indicated that it is easier to fracture the rock parallel to the.