The fracture behaviors of rocks under dynamic loading are significantly affected by flaws. Understanding regarding this fundamental mechanism flaw-induced fracturing could aid in reducing geohazards deep rock engineering. In study, a series experiments conducted on conjugate flawed white sandstone specimens to study the effect geometric configuration flaws fracturing. results show that geometry...

Traditional hydraulic fracturing theory believes that as the initial pore pressure increases, breakdown of rock will decrease. Previous experimental studies have shown may increase with (gradient), which cannot be explained by traditional theory. The current understanding effect and its gradient during is still unclear. In this study, analyzed based on a large number macroscopic microscopic phe...

Serious floor heave in gob-side entry retaining (GER) with fully-mechanized gangue backfilling mining affects the transportation and ventilation safety of the mine. A theoretical mechanical model for the floor of gob-backfilled GER was established. The effects of the mechanical properties of floor strata, the granular compaction of backfilling area (BFA), the vertical support of roadside suppor...

This study assessed the radiological health hazards to various body organs of workers working within Transnet Precinct in Richards Bay in Kwazulu-Natal, South Africa due to radionuclide content of mineral ores often stored within the facility. Thirty samples were collected from five mineral ores (rock phosphate, rutile, zircon, coal and hematite) and analyzed for 238U, 234U, 226Ra, 210Pb, 235U,...

The dynamic evolution characteristics of fracture are crucial to analyzing the development coal and rock mass instability, gas diffusion law, disaster prediction. These affect fractures gas-induced channels. Based on experimental results, we found following: In areas rich in both oil, damage due high-pressure oil was inversely correlated with distance from source. Moreover, as became closer sou...

Recent work at the Underground Research Laboratory of Atomic Energy of Canada Limited in Pinawa, Manitoba, has shown that high compressive stresses near the tunnel face significantly contribute to the loss of strength, and eventual failure of the rock, through stress-induced brittle fracturing. A program of laboratory testing has been undertaken to investigate the effects of brittle fracture on...