ONIYIDE GAFAR OMOTAYO picture
ONIYIDE GAFAR OMOTAYO

Publication

Publisher:
 24th International Mining Congress And Exhibition Of Turkey
Publication Type:
 Conference
Publication Title:
 Thermo-Mechanical Behaviour Of Rocks From The South African Platinum Mines
Publication Authors:
 G.O. Oniyide; H. Yilmaz
Year Published:
 2015
Abstract:

This paper presents the results of the study on the impact of temperature on the behaviour of selected rocks from the South African platinum mines. These mines are influenced by increasing temperatures due to high temperature gradient. The rock samples from the platinum mines were tested under varying confinements (10 to 30 MPa) and temperatures (20 to 140 °C) using servo-controlled testing machine. The results of the laboratory tests show that increasing temperature results in reduction of yield strength and Young’s modulus. Relationships between temperature and strength as well as the elastic modulus were established. These relationships would assist in the proper use of input parameters in numerical modelling exercises using the temperature option. The future design of deeper and warmer platinum mines would also hugely benefit from the knowledge of rock behaviour generated under high temperature and stresses.

 
Publisher:
 International Society For Rock Mechanics, 13th ISRM International Congress Of Rock Mechanics, 10-13 May, Montreal, Canada
Publication Type:
 Conference
Publication Title:
 Effect Of Temperature On The Dilatancy Of Rocks From The Bushveld Complex
Publication Authors:
 G.O. Oniyide; H. Yilmaz
Year Published:
 2015
Abstract:

This paper presents the result of the research done on the effect of temperature on the dilatancy of rocks from the Bushveld Igneous Complex (BIC), where the South African Platinum mines are located. The BIC has higher virgin rock temperature (VRT) than the gold mines of the ‘Witwatersrand Basin Complex’. If the platinum mines advance to ultra-deep levels as the gold mines, since the Merensky Reef has been reported to extend beyond 5km, then the virgin rock temperature at 5 km below surface would be approximately 140°C. Hence, there is a need for the investigation of rock behaviour at high temperatures. Five different rock types (norite, leuconorite, mottled anorthosite, pyroxenite and chromitite) were tested in a 2600 kN servo-controlled multi-purpose triaxial testing machine. The tests were done at a constant strain rate of 5 × 10-1 S-1and a confining pressure of 10 MPa within temperature range of 20 °C (ambient temperature) to 140 °C. The results show a general strength reduction and increasing dilation angles with increasing temperatures. The results also demonstrate that dilation angle is close to the internal friction angle at lower temperatures; however, they are greater at higher temperatures.