For underground mining and construction, it is important to obtain a discontinuities’ model of rocks for simulations to evaluate rock stability around the working space and fluid flow in these rocks. We have developed a method using the fractal property of acoustic emission (AE) source distribution to construct a feasible crack distribution model. We confirmed the usefulness of the model throug...

We study the structural instability mechanism and effect of a multi-echelon support in very-deep roadways. We conduct a scale model test for analysing the structural failure mechanism and the effect of multi-echelon support of roadways under high horizontal stress. Mechanical bearing structures are classified according to their secondary stress distribution and the strength degradation of the s...

A jointed rock mass presents a more complex design problem than the other rock masses. The complexity arises from the number (greater than two) of joint sets which define the degree of discontinuity of medium.  The condition that arises in these types of rock masses is the generation of discrete rock blocks, of various geometries. They defined by the natural fracture surfaces and the excavation...

Point load testing is used to determine rock strength indexes in geotechnical practice. The point load test apparatus and procedure enables economical testing of core or lump rock samples in either a field or laboratory setting. In order to estimate uniaxial compressive strength, index-to-strength conversion factors are used. These factors have been proposed by various researchers and are depen...

S resulting in sinkholes within dissolution mine fields in and around the city of Hutchinson, Kansas, USA (Figure 1) has been reported for more than 90 years. Salt dissolution and the resulting unpredictable upward migration of the dissolution voids can be observed both in proximity to well bores (dissolution mining, brine disposal, and oil wells; seismic shot holes, etc.) and in areas known to...

A literature review revealed that most of the empirical equations introduced for determination of the uniaxial compressive strength (UCS) of rocks based on the Schmidt hammer rebound number (N) are not sufficiently reliable mostly due to the relatively low coefficient of correlations. This is attributed to the fact that in most cases one formula is used for all types of rocks, altho...

Underground coal mining is one of the most dangerous occupations. Years of effort have been dedicated to researching methods of characterizing mine roof and floor for improving the mining environment. This research investigates using a neural network to classify rock strata based on the physical parameters of a roof bolting drill. This paper presents our methodology, as well as early results ba...

The mechanisms by which Cordilleran plutons are emplaced vary widely. However, the present authors have examined a series of plutons ranging from 2–35 km emplacement depth that have many common features, which suggest that downward transport of host rock is the most important mechanism during magma ascent and pluton emplacement. Many of these Cordilleran plutons preserve gently dipping, unfault...

Reducing the number of roof fall injuries is a goal of the NIOSH mine safety research program. Central to this effort is the development of assessment techniques to help identify the nature of the risks associated with working under potentially hazardous roof conditions. This paper discusses a method to determine the roof fall risk using a qualitative risk-analysis technique. The ability to det...

Cave backfill grouting implies grouting of the caving rock mass prior to it being compacted. The filling materials strengthen the caving rock and support the overlying strata to achieve the purpose of slowing down the surface subsidence. The broken roof will fail and collapse during mining operations performed without appropriate supporting measures being taken. It is difficult to perform conti...