Abstract

Raise boring machines (RBMs) are commonly utilized for drilling of shaft and other inclined structures in mining and civil applications. This paper aim to introduce several empirical equations to estimate the performance and operational parameters of RBMs. For the aim, datasets having rock properties including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), brittleness (BI), rock quality designation (RQD), elastic modules (E) and Poisson ratio (v); and also RBMs operational parameters including Instantaneous penetration rate (IPR), Specific Energy (SE), Pushing Force (Fpush), reamerhead power (Pw) and rotational speed (RPM), were established from published case studies. After that, re-established dataset was utilized to develop multiple regression models to predict the performance and operational parameters of RBM. It is found that IPR, SE, Fpush, Pw and RPM could be estimated using several alternative rock properties with coefficients of determination ranging from 0.77 to 0.95. Based on utilized dataset, it is also concluded that RQD and BI are the most common rock properties for estimating the performance and operational parameters of RBMs.

Introduction

In present, mechanical excavation takes a key role in the mining and tunnelling industry as an alternative to conventional drill and blast method. Many mechanical excavation machines have been historically designed to be utilized in different mining and civil construction projects. Mechanized excavation offers safer, faster, more efficient, and more environment friendly operations in excavation projects; However, the initial and capital cost of these machines are high and unable to cut very hard and very abrasive rocks [1]. Raise Boring Machines (RBMs) is an effective means of shaft construction where bottom access is available for removal of cuttings. Raise Boring Machines are one of the excavation machines for excavating vertical and/or inclined shafts and drifts such as ore passes, ventilation shafts and drifts, surge in hydropower plants, switching lines between underground subway tunnels (horizontal) and stairs tunnels (inclined) [2]. Access to both top and bottom locations of the hole is a prerequisite for conventional raise boring method. Application of RBMs to excavate the shaft can be found in the literature [2]. The performance and operational parameters of the mechanical excavators such as RBMs, roadheaders, and impact hammer should be estimated prior to starting the excavation operation to fulfill the economic requirements of the project.

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