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The objective is the study of filtering tissue permeability and the characterization by means of permeability tests, of the process of coal particles retention in breath protection filters. The porosity of a filter, defined as the ratio between the void volume inside its fibres and the total volume, is a static parameter that provides point source information about the initial conditions of the filtering tissue. When excessive deposition of particles on the fibres happens, there is an increase of resistance to the...

The uniaxial compressive strength (UCS) is one of the important input parameters used in rock engineering designs of underground spaces, or rock blasting, drilling, slope stability, excavation rate and many other civil and mining operations. Although, the method is relatively simple, it is time consuming and expensive; also, it requires well prepared rock cores. Therefore, indirect tests are often used to predict the UCS, such as Schmidt hammer, point load index and sound velocity. Besides, these indirect tests ca...

Characterization of rock masses is one of the fundamental aspects of rock engineering. Particularly, as a rock mass characteristic, determination of the strength of jointed rock masses is difficult since the size of representative specimens including discontinuities is too large for laboratory testing. This problem can be overcome by using the Hoek– Brown empirical failure criterion in conjunction with the Geological Strength Index (GSI) classification system. However, characterization of rock masses and determina...

Industrial processes do not get full efficiency and this means that a considerable amount of wastes without economical aim and which will finish in rubbish dumps, hence promoting a large environmental impact. Modern society steer itself, towards getting a sustainable development which minimize the production of these wastes, which are also increasing its economical, environmental and social costs. This fact compels to search solutions which could avoid the generation of this kind of wastes and to get value from th...