The first step in mining activities is rock excavation in both mine development and production. Constant pressure for cost reduction and creating an improved/safe work environment for personnel has naturally resulted in increased use of mechanical excavation systems in many mining operations. Also, mechanical excavation and mining is more compatible with automation, meaning possibility of reduction in number of people in the active underground mines. This factor plays a major role in selection of mining systems especially considering the dire shortage of skilled labour in the industry. While these systems are an integral part of mining activities in underground soft rock mining (coal, salt, potash, trona etc.), there is a need for developing new approaches and machinery for use in the underground hard rock mining. This paper will offer a review of current and emerging technologies for mechanical hard rock excavation, including disc cutting technology, drag picks, mini-disc, and activated/oscillating disc cutter. A review of general guidelines for assessment of the potentials of new research and development on this topic and evaluation of emerging technologies for a specific mining application will also be offered.

Specific energy is a key indicator of drilling performance to consider in the feasibility and economic analyses of drilling projects. Any improvement in the specific energy of a drilling operation may reflect an improvement in the overall efficiency of drilling operations. This improvement can be achieved by delivering a suitable cooling lubricant into the drilling environment. The present study examines the mechanical characteristics of the drilled rock, the physical qualities of the cooling lubricant employed, and the drilling rig operational parameters related to the drilling-specific energy (DSE). To this end, seven rock samples (granite, marble, and travertine) were drilled using water and five other fluids as the cooling lubricants. A total of 492 drilling experiments were conducted with a custom-designed and built laboratory-scale drilling rig on cuboid rock specimens. The univariate linear regression analysis of experimental results revealed a significant drop in DSE after using cooling lubricants instead of conventional cooling fluid (i.e. water). Under constant conditions in terms of mechanical properties of the rock, using Syncool with a concentration of 1:100 and soap water with a concentration of 1:120 instead of water led to 34% and 43% DSE reductions in the granite samples, 48% and 54% in the marble samples, and 41% and 50% in the travertine samples, respectively. These variations in specific energy suggest that the drilling efficiency and performance can be augmented using properly selected cooling lubricants.

Prediction of powder factor is a major activity while preparing drilling and blasting operation, as the total production cost depends on it. It is a major input parameter in blast design as it influences the efficiency of subsequent operations in mining. Generally, effective parameters that influence powder factor can be divided into three namely, rock mass, geometric and explosive parameters. In this study, the rock mass properties and geometric parameters were studied based on the ratio of the mass of explosive and blast design. The main objective of this study is the application of a rock engineering system (RES) to calculate the powder factor index (Pfi) based on predominant rock mass properties and geometric parameters. This approach was applied to a database of twenty-four blast sites comprising of rock mass rating, blastability index, porosity, specific gravity, uniaxial compressive strength, burden, the ratio of spacing to burden, ratio of drilled-hole depth to burden, drilled-hole diameter, and ratio of the burden to drilled-hole diameter. The relationship between these parameters and how each of them influences the powder factor was studied and used to predict the powder factor index. The result shows that rock mass rating, blastability index, porosity, specific gravity, uniaxial compressive strength, and drilled-hole diameter affect powder factor. It also shows that Pfi is a robust technique for generating an improved line of fit and predicting more dependable and accurate valuation of powder factor with the coefficient of determination (R2) of 0. 86, and root means square error (RMSE) of 0. 023 when compared with the traditional multivariable regression method.