Optimisation of open pit mine block sequencing

This study presents a comprehensive mathematical model for open pit mine block sequencing problem which considers technical aspects of real-life mine operations. As the open pit block sequencing problem is an NP-hard, state-of-the-art heuristics algorithms, including constructive heuristic, local search, simulated annealing, and tabu search are developed and coded using MATLAB programming language. Computational experiments show that the proposed algorithms are satisfactory to solve industrial-scale instances. Numerical investigation and sensitivity analysis based on real-world data are also conducted to provide insightful and quantitative recommendations for mine schedulers and planners.

Incorporation of human recombinant tropoelastin into silk fibroin membranes with the view to repairing Bruch’s membrane

Bombyx mori silk fibroin membranes provide a potential delivery vehicle for both cells and extracellular matrix (ECM) components into diseased or injured tissues. We have previously demonstrated the feasibility of growing retinal pigment epithelial cells (RPE) on fibroin membranes with the view to repairing the retina of patients afflicted with age-related macular degeneration (AMD). The goal of the present study was to investigate the feasibility of incorporating the ECM component elastin, in the form of human recombinant tropoelastin, into these same membranes. Two basic strategies were explored: (1) membranes prepared from blended solutions of fibroin and tropoelastin; and (2) layered constructs prepared from sequentially cast solutions of fibroin, tropoelastin, and fibroin. Optimal conditions for RPE attachment were achieved using a tropoelastin-fibroin blend ratio of 10 to 90 parts by weight. Retention of tropoelastin within the blend and layered constructs was confirmed by immunolabelling and Fourier-transform infrared spectroscopy (FTIR). In the layered constructs, the bulk of tropoelastin was apparently absorbed into the initially cast fibroin layer. Blend membranes displayed higher elastic modulus, percentage elongation, and tensile strength (p < 0.01) when compared to the layered constructs. RPE cell response to fibroin membranes was not affected by the presence of tropoelastin. These findings support the potential use of fibroin membranes for the co-delivery of RPE cells and tropoelastin.

A new open-pit multi-stage mine production timetabling model for drilling, blasting and excavating operations

This paper proposes a new multi-resource multi-stage mine production timetabling problem for optimising the open-pit drilling, blasting and excavating operations under equipment capacity constraints. The flow process is analysed based on the real-life data from an Australian iron ore mine site. The objective of the model is to maximise the throughput and minimise the total idle times of equipment at each stage. The following comprehensive mining attributes and constraints are considered: types of equipment; operating capacities of equipment; ready times of equipment; speeds of equipment; block-sequence-dependent movement times; equipment-assignment-dependent operational times; etc. The model also provides the availability and usage of equipment units at multiple operational stages such as drilling, blasting and excavating stages. The problem is formulated by mixed integer programming and solved by ILOG-CPLEX optimiser. The proposed model is validated with extensive computational experiments to improve mine production efficiency at the operational level.

Ideologies and their points of view

It is well known that different arguments appeal to different people. We all process information in ways that are adapted to be consistent with our underlying ideologies. These ideologies can sometimes be framed in terms of particular axes or dimensions, which makes it possible to represent some aspects of an ideology as a region in the kind of vector space that is typical of many generalised quantum models. Such models can then be used to explain and predict, in broad strokes, whether a particular argument or proposal is likely to appeal to an individual with a particular ideology. The choice of suitable arguments to bring about desired actions is traditionally part of the art or science of rhetoric, and today's highly polarised society means that this skill is becoming more important than ever. This paper presents a basic model for understanding how different goals will appeal to people with different ideologies, and thus how different rhetorical positions can be adopted to promote the same desired outcome. As an example, we consider different narratives and hence actions with respect to the environment and climate change, an important but currently highly controversial topic.

The long drive home: Control beliefs and commuting intentions of mine workers

Purpose: It is relatively common for many mine workers in Australia to drive an average of 250 kilometers to and from work following long shifts and shift blocks. Despite the long distances travelled following long shifts of 12- to 14-hours, there is evidence to suggest that these workers are not engaging in a break following their shift prior to driving home. This naturally raises issues of fatigue and sleepiness when driving. There is limited research in respect to commuting behaviours of mine workers and little is known about the factors that influence these workers to leave site immediately following their shift. Using the theory of planned behaviour, this paper examines individual control beliefs that encourage or prevent workers from leaving the site immediately following their shift block. Method: Data was collected using a cross-sectional survey. The survey instrument was developed following a series of in-depth interviews with workers from a Queensland coal mine (n=37). The quantitative written survey sample (n=461) was drawn from the same coal mine and consisted of workers from all levels of the organisation. Results: The results examine workers intentions to leave the work site and drive home immediately following a shift block. The results show differences in control beliefs between workers finishing night shifts compared with those finishing day shifts. Implications: An understanding of these control beliefs may potentially inform more targeted intervention strategies in the attempt to encourage a safer approach to driving home following shift blocks.

Role-based process view derivation and composition

The process view concept deploys a partial and temporal representation to adjust the visible view of a business process according to various perception constraints of users. Process view technology is of practical use for privacy protection and authorization control in process-oriented business management. Owing to complex organizational structure, it is challenging for large companies to accurately specify the diverse perception of different users over business processes. Aiming to tackle this issue, this article presents a role-based process view model to incorporate role dependencies into process view derivation. Compared to existing process view approaches, ours particularly supports runtime updates to the process view perceivable to a user with specific view merging operations, thereby enabling the dynamic tracing of process perception. A series of rules and theorems are established to guarantee the structural consistency and validity of process view transformation. A hypothetical case is conducted to illustrate the feasibility of our approach, and a prototype is developed for the proof-of-concept purpose.

Laboratory investigation on the effects of overburden pressure, water, and time on slaking induced material property degradation of coal mine spoil

In open-cut strip mining, waste material is placed in-pit to minimise operational mine costs. Slope failures in these spoil piles pose a significant safety risk to personnel, along with a financial risk from loss of equipment and scheduling delays. It has been observed that most spoil pile failures occur when the pit has been previously filled with water and then subsequently dewatered. The failures are often initiated at the base of spoil piles where the material can undergo significant slaking (disintegration) over time due to overburden pressure and water saturation. It is important to understand how the mechanical properties of base spoil material are affected by slaking when designing safe spoil pile slope angles, heights, and dewatering rates. In this study, fresh spoil material collected from a coal mine in Brown Basin Coalfield of Queensland, Australia was subjected to high overburden pressure (0 – 900 kPa) under saturated condition and maintained over a period of time (0 – 6 months) allowing the material to slake. To create the above conditions, laboratory designed pressure chambers were used. Once a spoil sample was slaked under certain overburden pressure over a period of time, it was tested for classification, permeability, and strength properties. Results of this testing program suggested that the slaking of saturated coal mine spoil increase with overburden pressure and the time duration over which the overburden pressure was maintained. Further, it was observed that shear strength and permeability of spoil decreased with increase in spoil slaking.

An integrated model of an open-pit coal mine: Improving energy efficiency decisions

This article contributes an original integrated model of an open-pit coal mine for supporting energy-efficient decisions. Mixed integer linear programming is used to formulate a general integrated model of the operational energy consumption of four common open-pit coal mining subsystems: excavation and haulage, stockpiles, processing plants and belt conveyors. Mines are represented as connected instances of the four subsystems, in a flow sheet manner, which are then fitted to data provided by the mine operators. Solving the integrated model ensures the subsystems’ operations are synchronised and whole-of-mine energy efficiency is encouraged. An investigation on a case study of an open-pit coal mine is conducted to validate the proposed methodology. Opportunities are presented for using the model to aid energy-efficient decision-making at various levels of a mine, and future work to improve the approach is described.

Evidence in view: Matton Developments Pty Ltd v CGU Insurance Limited [2014] QSC 256

Rule 478 of the Uniform Civil Procedure Rules 1999 (Qld)(view by court) is silent as to the manner in which a court might be expected to exercise the discretion to order an inspection or demonstration under the rule and also as to the use which may be made of any inspection or demonstration ordered. The decision in Matton Developments Pty Ltd v CGU Insurance Limited [2014] QSC 256 provides guidance on both matters. This case provides some guidance on the circumstances in which a court may exercise its discretion to order a view or demonstration

An alternative view of small firm adaptation

Increasingly, small firms with a history tied to a specific geographic location are having their survival threatened by new and innovative web-based entrants. This paper considers the plight of such firms and proposes an alternative means to reflect on how they may or may not learn about such threats. Adopting an evolutionary perspective, the construct absorptive capacity is used to highlight the deficiencies of current market orientation theory to explain the process of firm learning. The conceptual model of evolutionary potential provides a framework through which both the firm and its owner/s' abilities to learn can be taken into account.

An operational-level multi-stage mine production timetabling model for optimally synchronising drilling, blasting and excavating operations

This paper proposes a new multi-stage mine production timetabling (MMPT) model to optimise open-pit mine production operations including drilling, blasting and excavating under real-time mining constraints. The MMPT problem is formulated as a mixed integer programming model and can be optimally solved for small-size MMPT instances by IBM ILOG-CPLEX. Due to NP-hardness, an improved shifting-bottleneck-procedure algorithm based on the extended disjunctive graph is developed to solve large-size MMPT instances in an effective and efficient way. Extensive computational experiments are presented to validate the proposed algorithm that is able to efficiently obtain the near-optimal operational timetable of mining equipment units. The advantages are indicated by sensitivity analysis under various real-life scenarios. The proposed MMPT methodology is promising to be implemented as a tool for mining industry because it is straightforwardly modelled as a standard scheduling model, efficiently solved by the heuristic algorithm, and flexibly expanded by adopting additional industrial constraints.

Spotless decided per incuriam? - A contrary view

The article considers the implications of the decision of the High Court in Spotless Services Pty Ltd (1996) 141 ALR 92; 34 ATR 183. It argues in particular that the decision was made per incuriam.

Optimising the operational energy efficiency of an open-pit coal mine system

This thesis investigates factors that impact the energy efficiency of a mining operation. An innovative mathematical framework and solution approach are developed to model, solve and analyse an open-pit coal mine. A case study in South East Queensland is investigated to validate the approach and explore the opportunities for using it to aid long, medium and short term decision makers.

A “business researcher” view on opportunities for psychology in entrepreneurship research

In this short essay I offer some “business researcher” advice on how to leverage a strong background in psychology when attempting to contribute to the maturing field of “entrepreneurship research”. Psychologists can benefit from within-discipline research, e.g. on emergence, small groups, fit, and expertise as well as method strengths in, e.g. experimentation, operationalisation of constructs, and multi-level modelling. However, achieving full leverage of these strengths requires a clear conceptualisation of “entrepreneurship” as well as insights into the challenges posed by the nature of this class of phenomena.