Characterization of Soft Rocks in Brazilian Coal Beds

Abstract

Underground coal mining in Brazil is developed almost exclusively in the extreme South of the country. In the mid-1980s, an extensive work began on the geomechanical characterization of exploited or potentially exploitable coal beds through underground mining in the states of Rio Grande do Sul and Santa Catarina, southern Brazil, conducted by CIENTEC-Science and Technology Foundation of Rio Grande do Sul State. This chapter presents the geomechanical characterization of the most economically important coal seam mined in the South Catarinense Coalfield, southern Brazil (“Barro Branco, " “Irapuá, " and “Bonito”). The adopted in situ sampling procedures, the sample preparation techniques and the procedures used to carry out the petrographic, physical, and mechanical characterization tests in the laboratory, as well as the in situ tests, are detailed. The obtained results were statistically processed, making it possible to estimate the in situ strength of the coal layers for pillars dimensioning, as well as the typification of the main host rock lithologies present in the South Catarinense Coalfield for roof support system design.