Estimating rock properties using sound signal dominant frequencies during diamond core drilling operations

In many engineering applications such as mining,geotechnical and petroleum industries,drilling operation is widely used.The drilling operation produces sound by-product,which could be helpful for preliminary estimation of the rock properties.Nevertheless,determination of rock properties is very difficult by the conventional methods in terms of high accuracy,and thus it is expensive and timeconsuming.In this context,a new technique was developed based on the estimation of rock properties using dominant frequencies from sound pressure level generated during diamond core drilling operations.First,sound pressure level was recorded and sound signals of these sound frequencies were analyzed using fast Fourier transform (FFT).Rock drilling experiments were performed on five different types of rock samples using computer numerical control (CNC) drilling machine BMV 45 T20.Using simple linear regression analysis,mathematical equations were developed for various rock properties,i.e.uniaxial compressive strength,Brazilian tensile strength,density,and dominant frequencies of sound pressure level.The developed models can be utilized at early stage of design to predict rock properties.

深凹露天矿的人工通风

1 引言 露天开采是采矿工业的发展方向。随着露天矿山的迅速发展,采场深度逐渐增大。这些深凹露天坑将日益面临着自然通风的困难。然而,在露天开采的初期,人们并没有认识到人工通风的重要性。近十多年来,采场内的污染问题越来越严重地威胁着露天矿的生产和人员的安全。为此,本文将对深凹露天矿坑的通风设计作一阐述。