ENER20002Term 22017

Portfolio Assignment 2

Due date: / As per moodle site
Weighting: / To be advised or as per Unit Profile

This assessment relates to the following learning outcomes,

2.Identify and evaluate risks associated with different mining methods and operations

3. Generate and evaluate multiple mine design options

4. Present and defend a complex design and decision making process

Part A

Develop a spreadsheet-based model for a longwall mining operation. The purpose of this model is to compare various extraction strategies for safety, reliability and cost effectiveness.

Part B

Apply the model to the coal seam reserve shown in figure 1. Include the following parameters in your modelling.

  • Pit Pillar (100 m)
  • Seam thickness (3.6 m)
  • Main gate development dimensions
  • 4 headings (3.6 m x 4.5 m)
  • 3 pillars (8.0 m wide)
  • Main gate pillar width (50 m)
  • Head and Tail gate development dimensions
  • 2 headings (3.6 m x 4.5 m)
  • 1 pillar (8.0 m wide)

Reference your sources of information.

Figure 1. Coal Seam Reserve

The question should satisfy the following criteria of all learning outcomes with excellent.

LO 2 Identify and evaluate risks associated with different mining methods and operations.
Learning Element / Acceptable / Good / Excellent
2.1 Identifies and evaluates risks associated with extracting the maximum amount of coal. / Describes the risk associated with pillar sizes being too small or too large. / Identifies additional tonnes of coal that can be recovered with a 10% reduction in pillar size. / Evaluates the extra value of recovered coal against the risk of pillar failure or the cost of additional ground support.
2.2 Identifies and evaluates risks associated with longwall advance rate. / Explains the increased likelihood of AFC, hydraulic chock and shearer downtime due to wider panels. / Discusses the optimum panel size to ensure longwall component overhauls and rebuilds occur at change of panel. / Evaluates the risk of a slower advance rate against the efficiencies of wider panels. Evidence of research to determine actual downtime associated with longwall maintenance.
50- 65% / 65-85% / 85 -100%
LO 3 Generate and evaluate multiple mine design options
Learning Element / Acceptable / Good / Excellent
3.1 Uses a spreadsheet to model the extraction of a coal seam using a longwall mining method. / Identifies the tonnes of coal contained in the coal seam. Identifies the tonnes of coal the longwall can extract for a set of given parameters. / Models two different panel sizes and their impact on the recovery and production rate of the coal seam. / Models three different panel sizes, their consequent recoveries and production rates and their impact on the economic viability of the mine.
3.1 Explains the best sequence of mining for a longwall operation to extract coal efficiently. / Describes the various types of mining activities and critical equipment necessary to set up a longwall operation. / Identifies reasons for the size of various pillars and multiple headings. Explains why ground support in the main access headings would be more expensive than in the panel development headings. / Justifies the extraction of panels on retreat. Justifies the sequence of panel extraction based of conveyor installations and capacities. Justifies the need for development to be the optimum distance in advance of the producing longwall panel.
50- 65% / 65-85% / 85 -100%
LO 4 Present and defend a complex design and decision making process
Learning Element / Acceptable / Good / Excellent
4.1 Justifies the choice of a particular panel width for a longwall mining operation. / Uses industry standards to identify optimal panel width selection. / Justifies panel width based on results of modelling and evidence of design impacting on recovery and long term mine production rate. / Justifies panel width based on results of modelling and evidence of design impacting on recovery and long term mine production rate. Includes an economic justification of panel width selection.
50- 65% / 65-85% / 85 -100%

Reference your sources of information.