[email protected]
Support in Hard rock Underground Mines 3 Tensioned rockbolts are most effective in retaining loose blocks or wedges of rock near the surface of the excavation. These blocks may have been loosened by intersecting joints and bedding planes in the rock or they may
Slipjoint joint kit. 3.17 6.35 mm (0.125 to 0.250 in) wall split casing, stainless steel bands and band-it clips. The Urecon Slipjoint allows for expansion and contraction by having one end fixed while the other end is free to slide. Ideally suited to laid-on-grade pipe applications in the mining sector.
Feb 01, 2001 The CMRR was designed to evaluate the properties of the coal mine roof rock mass which contribute to its weakness and convert them into a relative strength rating from 0-100. These properties include the cohesion and frequency of discontinuities like bedding, slips, shears, and joints, UCS, and moisture sensitivity.
INTRODUCTION. Mining is particularly hazardous because of the nature of the work carried out. Averaging among all occupations in mines, underground coal mining activities are the most hazardous with very high risk (Shahriar et al., 2006).Surface mining is heeded to be more favourable and dominant than underground mining, particularly in safety, meaning, occupational risk in underground is much ...
Feb 01, 2020 Typical underground mining access is shown in Fig. 3. Excavations in underground mining projects are divided into the following two parts (Brady and Brown, 2006) Underground excavations for service purposes include mine access, ore drives, ventilation, crusher chambers and spaces for underground workshops.
Aug 01, 1991 United States. Nelson, W J. 1991. Mining problems caused by tectonic stress in Illinois basin. United States. abstractNote The Illinois basin coalfield is subject to a contemporary tectonic stress field in which the principal compressive stress axis ( sigma1) is horizontal and strikes N60 degreeE to east-west.
system would result more safer mining atmosphere and high productivity. Geological discontinuities are a prime causative factor in strata-movement problems in underground collieries. Faults (normal, bedding, slips and slickensides) are the most important causative factors in the roof-fall index followed by bedding planes, joints and cleats.
For the last 20 years, shotcrete has proven to be one of the most useful ground support elements in underground mining. The combination of cement, various additives (retarders, activators, reinforcing fibres etc.) and a mix of fine and coarse particles create a powerful tool for the mining industry.
Sep 21, 2016 Mining-induced landslide is a man-made geohazard that has drawn increasing public attention. Studies have shown that these landslides are generally triggered by a confluence of factors including underground mining, topographical and geological conditions (Sun et al. 2007).The underground mining activities may alter the stability of a slope by (1) generating cracks on the slope,
Jun 01, 2017 1. Introduction. Rockbolt is the most widely used support element in support systems in underground mines and civil tunnels. Rockbolting design is indeed mainly based on experience and it appears that rockbolting design is simply a business of selection of rockbolt types and the determination of bolt length and spacing, but, one essentially uses, either explicitly or implicitly, a
normal faults (trending ENE-WSW, E-W, and N-S), strike slip faults, columnar joints, folds, weak planes and quartz veins. The structural data is presented in figure 3.
tunnels and underground excavations - tunnels and underground excavations - Tunneling techniques Tunnels are generally grouped in four broad categories, depending on the material through which they pass soft ground, consisting of soil and very weak rock hard rock soft rock, such as shale, chalk, and friable sandstone and subaqueous. While these four broad types of ground condition
7. Underground mining Example of a fall of ground on gemfields. Fall is from roof and sidewall contact. For safety reasons you should have a partner when underground mining. When first starting out in an opal or gem mining area, it is advisable to ask local miners what the ground is like where you are considering digging. Places to avoid may ...
Perenti Global Limited (Perenti) is a diversified mining services company listed on the Australian Securities Exchange (ASX PRN). Since the companys formation in Kalgoorlie in 1987, Perenti has grown significantly and the Perenti group of companies (Group) now has operations and offices across 12 countries and is involved in some of the worlds largest surface and underground mining ...
The rock mass of deep underground engineering is in the complex geological environment of high stress, high temperature, and high water pressure. In the process of deep mining and underground space development, the fault-slip seismic source may cause engineering accidents with strong destructive capacity. An in-depth study of fault slip characteristics is very important in the engineering ...
Strike-slip fault Strike-slip faults usually have very steep or vertical dips and the relative movement between the adjacent blocks is horizontal, parallel to the strike of the fault plane. Large strike-slip faults are referred to as transcurrent faults and wrench faults.
controlled by three fundamental elements geomechanical conditions, stress state and mining activities. The term geomechanical conditions include intact rock with geological structures (joints, faults, folds etc.) and it is characterized by the strength and stiffness
pillar with adit and joints, scale physical models were used from equivalent materials. Slips and bumps were also studied mathematically. The solution must allow an extrusion of rock into an open space (for bump study only). Keywords mining, rock mechanics, mathematics and physical modelling, joints, rock pillar, cave-in, rock burst, bump.
Joint Sets Vertical cracks in strata (shale, sandstone, etc.) that tend to fill with sediment over millions of years (thus the term mud seams). Tend to occur at regular intervals. Result in fall of rock (can be major) in face of highwalls when toe weakens or when two intersecting joints develop a wedge (chimney) that
critically important in the design of underground excavations, it follows that a stress measuring programme may be required in any major underground mining or civil engineering project. Developing a stress measuring programme Consider the example of a tunnel to be driven a depth of 1,000 m below surface in a hard rock environment.
Mar 02, 2019 Following rainfall, variations in groundwater turbidity may be an indicator of surface contamination. Can be caused by decaying leaves, plants, organic matter, copper, iron, and manganese, which may be objectionable. Indicative of large amounts of organic chemicals, inadequate treatment, and high disinfection demand.
Jul 15, 2020 Muography is a novel imaging method using natural cosmic-ray radiation for characterising and monitoring variation in average material density in a diverse range of objects that cannot be imaged by conventional imaging techniques. Muography includes muon radiography and muon tomography. Cosmic-ray-induced muons were discovered in the 1930s, but rapid development of both muographic ...
in Burst-prone Underground Mines. The workshops focused on aiding the mining industry to identify and characterize Fault Slip potential. Assessing whether faults will slip is a major concern for deep mining. Un-expected movement induced by mining extraction can, in the worst situations, lead to rock bursts, which can have major adverse impacts.
The interaction between rock joints and seismic waves is critical in rock engineering when rock mass is suffered from human-induced or natural earthquakes. Stress wave propagation across rock joints is usually dependent on the seismic response of the joints. Wave propagation may cause joints close or open under the in situ stress. In this paper, the seismic response for wave propagation with ...
MINE 202 SURFACE MINING CHAPTER 2 UNIT OPERATIONS IN MINING f Lecture Objectives At the end of this lecture, you will 1.Understand the sequence of unit operations. 2.Know the main and auxiliary equipment used for loading and haluage. 3.Know how to calculate stripping ratios. 4.Know the stipping ratio models. 5.Know how to calculate cut-off ...
Cook, N. G. W., 1992, Natural joints in rock Mechanical, hydraulic and seismic behavior and properties under normal stress International Journal of Rock Mechanics Mining Science Geomechanics Abstracts, 29, 198223, doi 10.1016/0148-9062(92)93656-5.
Dec 26, 2018 Abstract. The rock mass around an excavation is generally traversed by different geological discontinuities such as faults, folds, slips, joints, etc. Fault is one of the major geological discontinuities which creates lot of difficulties during underground winning of coal. Entire stress regime and ground conditions in the formation are altered in and around the faults.
ministration (MSHA) are numerous references to slips, horsebacks, faults, coal streaks, clay veins, joints, and rolls.2 These are all geologic defects or weaknesses in the roof that were not anticipated or adequately supported. The ground control program at the Pittsburgh Research Labo-
underground mining work and can only be done effectively for a comparatively short period ... detection of joints, cracks, etc. The application of water to certain ground conditions, eg some highly stressed ground, ... the person to slip or fall.
Product features of slip type expansion joints Slip type expansion joint uses new seal material flexible graphite ring, with strong strength, low friction coefficient (0.04 0.10), not aging, effect is good, convenient maintenance, etc. The service life of the slip type expansion joint is long fatigue life is the same with pipeline.
joints 5 Continuity of joints 5 Ground Water 10 10 10 10 15 Weathering 9 Condition of joints 15 30 25 30 Strike and Dip orientation 15 Strike and Dip orientation for tunnels 3-15 0-12 0-12 0-12 The main factors that have been changed with the RMR system are the weightings given to joint spacing, joint condition and ground water. In
mining through major scale underground stoping zones presents both a risk and challenge that can have significant ... slips and joints) Underground level and stope mapping and history ... etc.) Delineator cones and pickets. The type and
Deepwater rigs use telescopic joints, or slip joints, to connect to a drilling riser and accommodate vertical motion from vessel heave. The elastomeric seals in these joints experience extreme friction, resulting in material loss. Seals designed with LORD wear-resistant nitrile have been shown to last 20X longer than traditional nitrile. See ...
Surface Rock Support of Underground Mines Code of Practice 1.0 INTRODUCTION Rock falls are an ever-present hazard in underground mining, especially in unsupported ground. They are primarily caused by discontinuities and/or high or low adverse stresses in the rock mass. The intersection of three or more joints or fractures with the back, face or
component of any successful mining project. A ground control management plan* would include pre-mining investigations of ground conditions*, development of a mine plan and design according to the assessed ground conditions* and required rates of production etc .. Once mining is underway, a system of ground performance monitoring and re ...