Explosives and timed detonators delay detonatorsare then placed in the blast holes. Short lengths of pvc pipe were inserted into the blast holes as scan aids so that the laser scanner could accurately capture collar locations as well as hole orientations. The method can be used in all types of rocks and the initial cost is lower than the mechanical method like tbm. When choosing a drilling method, especially for exploration and grade control, one must consider many factors such as cost, time, environmental impact, depth of drilling and sample quality. Blast database content a blast search has four components. Bender 1999 defined production blasting as the type of blasting that is designed to fragment a predetermined volume of rock. Drill monitoring systems and the integration with drill and blast software john hutchings, datavis pty. For example, the specific charge at tunneling is 310 times higher than at bench blasting, depending on borehole deviation, tight. The shaft bottom is cleaned after mucking, the center line fixed by plumb bob, and the next round drilled.
This leaves us free to select the best product for the job and focus on optimising the blast to use as little product as possible while ensuring quality and productivity targets are met to save the client costs. Drill and blast method is mostly used method for the excavation throughout the world. The size of the mast and drill steels carried by the rig are important considerations in drilling efficiency. Parts of this thesis may be used in a further global study which sandvik and ita is considering to start about the same subject.
Direct air rotary drilling down the hole hammer drillingdiscussed in separate sectionin air rotary drilling, air alone lifts the cuttings from theborehole. Study and quantification of tunnel works by drilling and blasting method. Most of the openings were developed by the drill and blast method, but the lower 50 m of the main tunnel approx. For starters, excavation using tbm is mechanized, with a huge tunnel boring machine piercing the rock with its rotating drilling head and removing the spoil. Determine pounds of explosivefoot of powder column.
The continuous development of equipment, particularly for drilling, and the development and improvement of explosives helped drill and blast to achieve a considerable significance. It was the primary means of tunneling through rock prior to the advent of tunnel boring machines. Blast plan a written procedure that details the methods and manner by which a project blaster will comply with pertinent laws, rules, regulations, and contract documents. Description of construction methods and activities a. Concrete is mixed on the surface and conveyed down the shaft in a pipe. Mar 14, 2016 when choosing a drilling method, especially for exploration and grade control, one must consider many factors such as cost, time, environmental impact, depth of drilling and sample quality. Correspondingly, the selected mining process is a consideration in development of the comminution circuit design. The level of automation and mechanization of these tasks is low and there is a high degree of hard manual labor involved. Mar 19, 2018 isometric explainer animation for drill and blast tunneling method. Mechanical excavation miners, tbm advantages of drill and blast method. Mosher, in gold ore processing second edition, 2016. Mainly used in rock formations, several variants exist including the mining method, drill and blast method, new austrian tunneling method, etc. Drillandblast method the advancement of long tunnels through hard rock well before tunnel boring machines tbms were invented relied entirely on the drillandblast method.
Compared with bored tunneling by tunnel boring machine, blasting generally results in higher. Other work 4 has been directed to the utilization of explosive. Shot drills rotary drill whose bit consists of a steel pipe with a. Xc11 blast round the xc11 entry was the end ore panel on the 7170 level. Drill monitoring systems and the integration with drill.
If the blastholes are drilled as a staggered pattern on an equilateral triangular grid, the optimum distribution of the. Knowledge of mathematical formulas will provide ease in designing a blast that will be safe as well as effective. Were actually talking about two very distinct methods. For efficient operation, more personnel are generally required than for other drilling methods. A common way of designing a blast is using the powder factor method. In hard rock conditions, road headers cannot be used effectively, so disc cutting is the first for excavation of declines, tunnel boring machines tbm can be used in many cases. Drill and blast is one of the first processes to happen in an operation and can determine the effectiveness of subsequent activities, ensure it is done right by utilising the drill and blast module to store, compare and report design. Most of the openings have an areal size range of 2535 m 2. Terms in this set 19 options for development of drifts and ramps are. Ad757 114 study of a1 continuous drill and blast tunneling. The decision whether to construct a tunnel using a tbm or using a drill and blast method includes a number of factors. Drill and blast tunneling is a method of excavation involving the controlled use of explosives to break rock. If a quarry plans to use 30foot bench heights with 7 feet of subdrill, a drill rig. Underground mining methods and fundamental principles.
Before the blast hole drilling can begin, the proposed site needs to be inspected, and certain decisions need to be made with regards to the hole sizediameter, the type of drill or drills that will be required, etc. Conventional drifting or tunneling by drilling and blasting method requires a much higher specific charge than ordinary production blasting such as bench blasting. Depending on the length of the tunnel, the rock conditions and the proximity to critical structures, tunneling by drill and blast hand mining can be accomplished as safely as the tbm method yet can be more economical. A case study examination of two blast rounds at a nevada. Abrasive blasting operations, engineering control and work. Blast basic local alignment search tool blast program selection guide table of content 1. The critical drill features are pull down force, rotation power, and compressor capacity. Methods for evaluating drill pattern parameters such as burden, spacing, borehole diameter, etc. At frontierkemper we are skilled at conventional drillandblast excavation as well as the shotcrete method also known as the sequential excavation method or new austrian tunneling method highway tunnels are often large in crosssection and require conventional drillandblast excavation methods. Tunnel length is a key issue that needs to be addressed because large tbms for a rock tunnel have a high capital cost, but because they are usually quicker than a drill and blast tunnel the price per metre of tunnel is lower. The success of achieving these goals depends significantly on good blast design. Software would later be used to estimate the 3d location of each drill hole in space to its full depth. To achieve a good blast design, an understanding on the rock dynamic response. An introduction to reverse circulation drilling castle drill.
Blast pattern the plan view of the drill holes as laid out for blasting. Like trenchless construction and horizontal directional drilling, drill and blast tunneling is a form of subsurface construction. The drill and blast tunnel method is not always considered to be an option. Today, the drillandblast method is still widely practiced and used in building tunnels through hard rock where the use of tunnel boring machines is not. Drill monitoring systems and the integration with drill and. Drill depths are accounted for more accurately, making it easier to assign the right amount of explosives in blasting. With explosives contributing to 50% to 75% of a drill and blast project costs, big savings can be achieved. At frontierkemper we are skilled at conventional drill and blast excavation as well as the shotcrete method also known as the sequential excavation method or new austrian tunneling method highway tunnels are often large in crosssection and require conventional drill and blast excavation methods. Compared with tbm technology, the performance rate of advance for drill and blast excavation is lower in most cases. Drill bit development rapid advances in drill bit technology have also occurred throughout the last 40 years. Further, the drill and blast method is characterized by a short mobilization time requirement due to the use of standard equipment. Drill and blast drilling and blasting miplan solutions.
Once blasting is carried out, waste rocks and soils are transported out of. The hardness, toughness and strength of the rock to be drilled determine the requirements for the drilling tools. Some drill sites are inaccessible because of the rig size. Pdf drilling and blasting as a tunnel excavation method. Mechanical excavation methods are a step change in excavation performance and labour safety compared to drill and blast operations. Blasters training modules module 4 blasthole drilling.
New gpsenabled applications have improved strata recognition capabilities that help drill and blast engineers develop more appropriate and more suitable blast designs. The data was collected from literature and standard collection of each country. Van ruth core orientator is based on gravity and only works consistently and effectively for. One method involves accumulating the burden contributed by successive layers of rock and matching the accumulated rock burden to a target value for a borehole having a length related to the average height of the layers. Oct 23, 20 the continuous development of equipment, particularly for drilling, and the development and improvement of explosives helped drill and blast to achieve a considerable significance. May 26, 2016 the shaft of mansar and balaghat mines have made by conventional shaft sinking method but if this shaft would have been sunk with the advanced technologies like vsm and shaft borer the production rate would have been raised to 30 % marks, 2002 with the sophisticated usage of manpower, increasing safety and reducing cost of capital on shaft.
The size reduction process starts with mining, and the degree of fracturing and breakage achieved in drill and blast is an important factor in comminution circuit performance. Van ruth method comprises an instrument with a conical probe and finger pins along end that is connected to the core barrel and pushed downhole against the core stub left by the previous drill run. Conventional tunneling has the following steps fig. Van ruth core orientator is based on gravity and only works consistently and effectively for inclined. The drill and blast method table 1 is characterized by operations that occur in a repeated cyclic sequence. Zongxian zhang, in rock fracture and blasting, 2016. Introduction this chapter describes the construction process for the second avenue subway. This document is also available in pdf 163,516 bytes. If a quarry plans to use 30foot bench heights with 7 feet of sub drill, a drill rig. Ppt study and quantification of tunnel works by drilling. Drill and blast this tunnelling method involves the use of explosives. The total labor cost for drill and blast tunneling is high, but the total investment cost is. Vibration control in urban drill and blast tunneling. Lecture 4 drifting, drilling, blasting and scaling.
Reverse circulation drilling offers many advantages over other drilling methods, such as rotary air blast drilling or diamond drilling. Potential environmental impacts that could result from its construction, as well as mitigation measures to lessen their effects, are discussed in subsequent technical chapters. This tunneling method involves the use of explosives. Drilling rigs are used to drill blast holes on the proposed tunnel surface to a designated depth for blasting. Study of a continuous drill and blast tunneling concept 4. Explanation for the program choices given in tables 3. For optimum hole cleaning, the outside diameter of the drill pipe must be balanced with the hole size and air compressor. Descriptive notes 2ype of rpeoi and incluoie dates final report, aug. A better drill and blast solution for the coal sector. Isometric explainer animation for drill and blast tunneling method. In direct air pressure blasting, the abrasive is fed from a pressurized contali er pressure vessel into a blast hose, as shown in figure 112. The order and timing of the detonation of the individual blast holes is regulated by the initiation system. Drilling and blasting an overview sciencedirect topics.
168 1600 1536 1329 1181 920 356 691 504 1455 878 1467 1623 390 854 82 1301 989 1376 767 1079 283 1152 1500 335 233 442 948 605 1187 964 228 652