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...

Understanding the strength and slip behaviour of tectonic faults is a central problem in earthquake physics and seismichazard assessment1–8. Many major faults, including the San Andreas Fault, are weak compared with the surrounding rock, but the cause of this weakness is debated1. Previous measurements of the frictional strength of San Andreas Fault rocks are too high to explain the observed we...

The CERCHAR abrasivity test is very popular for determination of rock abrasivity. An accurate estimation of the CERCHAR abrasivity index (CAI) is useful for excavation operation costs. This paper presents a model to calculate CAI based on the gene expression programming (GEP) approach. This model is trained and tested based on a database collected from the experimental results available in the ...

The teeth of limpets exploit distinctive composite nanostructures consisting of high volume fractions of reinforcing goethite nanofibres within a softer protein phase to provide mechanical integrity when rasping over rock surfaces during feeding. The tensile strength of discrete volumes of limpet tooth material measured using in situ atomic force microscopy was found to range from 3.0 to 6.5 GP...

The experiments of Forbes and his associates (5) ^ at the Ohio Agricultural Experiment Station defined in a very complete fashion the relative efficiency of several mineral compounds as calcium supplements in swine nutrition. The minerals tested included limestone floats, precipitated bone flour, special steamed bone flour, rock phosphate floats, and precipitated calcium carbonate. As compared ...

a r t i c l e i n f o In many mining, civil, and petroleum engineering applications diamond bit drilling is widely used due to high penetration rate, core recovery and its ability to drill with less deviation. Recently, many research have been conducted to estimate the penetration rate of diamond drilling which can be considered as one of the most important parameters in project planning and co...