Samuel Frimpong

Derivative mine valuation: strategic investment decisions in competitive markets

Abstract Successful management in competitive markets requires evaluation methods that respond to global market dynamics and provide investors with relevant information to make strategic investment decisions. These strategic decisions include decisions on investment timing, feasibility study and risk management and mine operating options. Conventional methods do not have the built-in capabilities to help investors handle these strategic issues. Advances in modern finance have had profound impacts on financial markets for options, futures and collaterized securities and offer appropriate tools in solving these problems. In this paper, the authors have extended the Brennan and Schwartz mineral resource model to develop the derivative mine valuation method based on the dynamic arbitrage theory. A copper mining venture has been evaluated using the derivative mine valuation and conventional methods. The results show that the derivative mine valuation method allows investors to maximize the ventures market value by exercising these strategic options.

Virtual prototype simulation of hydraulic shovel kinematics for spatial characterization in surface mining operations

Hydraulic shovels are large-capacity equipment for excavating and loading dump trucks in constrained surface mining environments. Kinematics simulation of such equipment allows mine planning engineers to plan, design and control their spatial environments to achieve operating safety and efficiency. In this study, a hydraulic shovel was modelled as a mechanical manipulator with five degrees of freedom comprising the crawler, upper, boom, stick, bucket and bucket door components. The model was captured in a schematic diagram consisting of a six-bar linkage using the symbolic notation of Denavit and Hartenberg (Ho and Sriwattanathmma 1989). Homogeneous transformation matrices were used to capture the spatial configuration between adjacent links. The forward kinematics method was used to formulate the kinematics equations by attaching Cartesian coordinates to the schematic shovel diagram. Based on the kinematics model, a 3D virtual prototype of the hydraulic shovel was built in the Automatic Dynamic Analysis of Mechanical Systems (ADAMS) environment to simulate the motions of the hydraulic shovel with selected time steps. The simulator was validated using real-world data with animation and numerical analysis of the digging, swinging and dumping motions of the shovel machinery. The superimposed display of the deployment of the hydraulic shovel in three phases allows a detailed motion examination of the system. The numerical results of linear and angular displacements of the bucket tip and bucket door can be used to analyse the kinematics motion of the hydraulic shovel for its optimization. This simulator provides a solid foundation for further dynamics modelling and dynamic hydraulic shovel performance studies.

Intelligent Modeling: Advances in Open Pit Mine Design and Optimization Research

Design and optimization of pit layouts yield the mineable ore reserves and minimum waste to maximize the net pit value and to ensure optimum location of surface facilities. Many algorithms and their modifications, derived from stripping ratio concepts, displacement of conic volumes, dynamic programming and graph theory, have been developed to design and optimize pit layouts. These algorithms have assisted engineers in making design decisions but they are limited in dealing with pit design stochastic processes. Large information and database and the requirement for complete rerun of these algorithms with information and data changes result in long computations and CPU times. Current algorithms do not provide analysts with intelligent design options to deal with structural, hydrological and tectonics problems of mine design. In this paper, the authors discuss current state-of-the-art technology and research in intelligent modeling. Current and future research frontiers in intelligent modeling are also addressed with emphasis on developing efficient and user-friendly technology for pit design and optimization.

Modelling Open Pit Dynamics Using Discrete Simulation

The objective in any mining operation is to exploit ore at the lowest possible cost with the prospect of maximizing profits. The planning of an open pit mine is an economic exercise, constrained by certain geological, operating, technological and local field factors. Heuristic methods, economic parametric analysis, operations research and genetic algorithms have been used to formulate periodic open pit planning problems. Open pit design, optimization and subsequent materials scheduling problems are governed by stochastic dynamic process. Thus, current algorithms are limited in their abilities to address problems arising from these random and dynamic field processes. The primary objective of this study is to use a discrete stochastic simulation to capture the random field processes associated with open pit design and materials scheduling. An open pit production simulator (OPPS), implemented in MATLAB, based on a modified elliptical frustum is used to model the geometry of open pit layout expansion. The simulator mimics the periodic expansion of the open pit layouts. The interaction of the open pit expansion model with the geological and economic block model returns the respective amount of ore, waste, stockpile materials, and the net present value of the venture. A case study of an iron ore deposit with 114 000 blocks was carried out to verify and validate the model. The optimized pit limit was designed using the Lerchs – Grossman algorithm. The best-case annual schedule, generated by the shells node in Whittle Four-X, yielded a net present value (NPV) of

Parametric Simulation of Shovel-Oil Sands Interactions During Excavation

414 million over a 21-year mine life at a discount rate of 10% per annum. The best scenario out of 5000 simulation iterations using OPPS resulted in an NPV of

Hybrid Simulation for Oil-Solids-Water Separation in Oil Sands Production

422 million over the same time span. Further research, based on hybrid stochastic simulation in conjunction with reinforcement learning, can provide a powerful tool for addressing the random field and dynamic processes in long-term open pit planning.

Mechanics of Oil Sands Slurry Flow in a Flexible Pipeline System

Hydraulic shovel excavators are widely used as primary production equipment in surface mining for removing overburden and ore materials. Variability in material diggability, unstructured mining environments and limited space, effective machine operation, and machine logistics affect the performance of the hydraulic shovel excavators. A hydraulic shovel simulator is developed to simulate the performance of hydraulic shovels for oil sands extraction in the ADAMS simulation environment. The shovel-oil sands interaction is simulated using a reformulated universal earth-moving model. The simulated digging parameters include the bucket dynamics, oil sands properties, oil sands-bucket interactions, and operating variables. The results show that the simulator is capable for identifying the parameters, which influence the performance of hydraulic shovels. This parameterized simulator provides a powerful tool for performance monitoring, excavation process designs and structural optimization of hydraulic excavators. The method presented in this paper forms the basis for developing comprehensive simulator models for automated shovel operations in constrained mining environments.

Stochastic-Optimization Annealing of an Intelligent Open Pit Mine Design

Abstract Separation of oil-sand-water mixtures is vital in oil sands production and processing. The co-existence of sand and oil in oily water systems can cause corrosion problems to the operational facilities and equipment. Immoderate oil and oil-coated sand levels have negative impacts on the environment. This research attempts to provide further understanding and some solutions to this problem by hybridization of two hydrocyclones for solid-liquid and liquid-liquid separation. The hybrid hydrocyclone is hydrodynamically designed to incorporate a transverse aperture for sand rejection, a transformation of which enables concurrent liquid-solid-liquid three-phase separation of the oily sands. Through computer simulation, the hybrid hydrocyclone has demonstrated promising performance in separating oil-sand-water in a single-stage oil sands production operation. For concentration up to 40% by mass of feed there was good s stability and accuracy in the model determination. Beyond that, droplet degeneration and breakup and bedding, and bridging of the hybrid spigot by sand characterized poor accuracy. Two distinct phases of behaviour were exhibited in the hybrid model — collinear velocity spectra as the forced vortex flow emanated through a 5-mm radius cylindrical envelope co-axial with the hybrid and parabolic spectra as the flow proceeded beyond this transition envelope towards to its wall liberating the vortex.

Dump truck operator vibration control in high-impact shovel loading operations

Slurry transportation is an economic haulage system in oil sands and coal-mining operations characterized by long haulage distances and rugged terrain. In such conditions, the ton-km-hr limits are exceeded creating extreme tire wear and high maintenance costs. Steep haul grades and rugged terrain also cause mechanical wear and tear, which decrease haulage equipment economic life. Hydraulic transportation is a proven and viable technology for slurry transportation in such conditions. Currently, stationary pipeline transportation is being used in transporting minerals in many mines. There is an increasing demand to create slurrified minerals at the mining faces to be transported to the processing plant. However, stationary pipelines are not capable for dealing with the rapidly changing configuration of the mining faces. In this paper, the authors develop the ground articulating pipeline (GAP) technology to address this problem. The GAP system consists of pipelines connected together with flexible joints in each pipe section, which allows deflection to avoid torsional stresses from the adjoining frames. This flexible arrangement accommodates the horizontal and vertical displacements of the mobile system as it follows the hydraulic shovels in the excavation process. The mechanics of the GAP system, as well as the production–economic function, are formulated and simulated over an extended period using data and information from Syncrude’s North Mine. The results show that the GAP system is technically and economically viable for productivity between 6,300 and 6,500 tons per hour. The simulated head loss for the GAP system is 15.66 m per 400 m, which compares with 20 m per 400 m for the existing stationary system at Syncrude. The pressure gradient-radius curves are asymptotic to the pipe boundaries, which indicates steep axial pressure gradient in these areas.

Dragline dynamic modelling for efficient excavation

Optimized pit layouts are used to extract mineable reserves with minimum waste under geological, geotechnical and property boundary constraints and to develop strategic and tactical production plans for achieving corporate goals. Pit design and optimization algorithms are limited in dealing with the random field properties of these layouts resulting in sub-optimal results. Database changes require complete rerun of these algorithms resulting in long CPU times with no allowance for incorporating operating strategies. In this study, the authors develop an intelligent pit optimizer, IPOP, to solve these problems. It combines stochastic models of ore reserves and commodity prices to generate economic block and target values. The error backpropation algorithm is used to train the neural network for block pattern recognition and partitioning based on the target values. The PITSEARCH program is then used to search for the optimized layout under the pit slope constraints. Stochastic-optimization annealing is carried out to examine the random field properties of the optimized pit value. IPOP is used to optimize Section SBHP 860001 of the Sabi open pit in Zimbabwe, and the results are compared with that from the 2D Lerchs-Grossmanns algorithm. The two algorithms yield the same value of Z