Mine Power Supply and Drainage
Mine Drainage Design Task
If required it may be assumed that g = 9.81 m/s2, Density of water = 1000 kg/m3,
You are a mine planning engineer at a medium sized operation producing 1.5 mtpa of coper ore at 3% Cu. The mine was originally designed using a bench height of 15m. Footwall benches were 15 m wide to give a slope angle of 45°, but on the hanging wall side alternate benches are only 10m wide to produce an angle of about 50°.
You are required to design a drainage and pumping system to deal with the mine water for the next 10-15 years based on the data in the following sections. As the mine grade is low and power costs are high every effort should be made to minimise the operating costs of the pumping system. Describe your proposed drainage and pumping system with the aid of diagrams where required and explain the general philosophy behind the system. Detail and assumptions made and make comments and conclusions as required.
Data
Mine water
Ground water: currently averages 1,000,000 litres/day and is expected to increase at a rate of 5% per year as the mine deepens.
Mine water: averages 50,000 l/day with small variations in use on an hour by hour basis.
Water Quality: Run of mine water is expected to be slightly acidic due to the formation of sulphuric acid from sulphides within the rock
Rock properties: SG of 2.9 for all rocks. Hanging wall and ore have moderate strength, footwall is very strong.
Electrical Design Task
The purpose of this assignment is for the student to design an electrical distribution system for the coal mine illustrated in Figure 1.
Figure 1: schematic diagram of underground workings.
The mine is to operate a single retreating long wall coalface at any one time. Whilst this face (panel 1 on the figure) is in production the next panel is under development. The physical dimensions of each airway in the system are as listed in Table 1. All airways excepting the drift and shaft are developed fully within the flat coal seam of 3m thickness. A ventilation fan is located at the top of the return ventilation shaft that can in emergency situations act as a second means of egress.
Coal clearance is undertaken by conveyor, conveyors are located in airways 1-2, 2-5, 5-7, 5-6, 7-10, 10-11, 11-12, 12-13 and 7-14 with an armoured face conveyor located on ht face 6-8. Development is undertaken using continuous miner. Table 2 lists the electrical machine requirements and location for the time frame under consideration.
Distribution voltage at the mine is 13.2 kV.
The purpose of the exercise is to devise an electrical distribution system to service the current and possible future requirements of the mine. The student is to consider the following:
- Cables and cable couplings
- Switchgear
- Transformers
- Power centres
- Distribution and utilisation systems
- Electrical safety
- Control requirements
- Any other requirements
- Power factor correction (if required)
All assumptions need to be detailed and justified. The results should be presented as a report; no page limit is specified, with diagrams and other data as required. Students should note that there is no single answer to this design, marking will be based on the robustness of the system, the inherent safety of the system and the ability of the system to be expanded. In order to aid on the last criterion it is expected that the life of an individual panel is of the order of 6 months under the current production schedule, the extracted length of all panels in the mine is 1950m, i.e. a 50 m barrier pillar is required.
Attachment:- Assignment.rar