ENMIN 5100 Mine Power Supply and Drainage
Electrical Design Task
Answer all questions (worth 30% of total assessment)
Due Date 28/02/2015
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, 25, 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 13,000V.
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.
Table 1: Dimensions of mine.
Branc
h from Branch
to Length (m) Width (m) Heigh
t (m) Comments
1 2 2400 5 4 Intake drift 1 in 6
2 3 200 5 3 Cross cut
2 5 150 5 3 Intake
5 7 100 5 3 Intake
5 6 2000 5 3 Panel 1 intake airway
6 8 250 5 3 Panel 1 face
8 9 2200 5 3 Panel 1 return airway
7 10 650 5 3 Intake
10 11 200 5 3 Cross cut
11 12 400 5 3 Return
12 13 500 5 3 Panel 2 return airway daed end development
12 9 100 5 3 Return
7 14 2150 5 3 Panel 2 intake airway development
9 3 350 5 3 Return airway
3 4 400 4.5 Return shaft (circular)
Table 2: Major items of electrical equipment to be considered within the exercise
Item of
equipment location Power (kW) Voltage (V rms) Comments
Panel 1 shearer
(coal cutter) Anywhere on
coal face 500 1100 Max length of cable from intake end of face = 250m
Panel 1 return end AFC drive Node 8 225 1100 Directly coupled to intake end AFC motor
Panel 1 intake end AFC drive Node 6 225 1100 Directly coupled to return end AFC motor
Stage loader
motor 200m from node 6 in panel 1
intake 225 1100 Phased to start prior to AFC
Panel 1 hydraulic power pack 150m from node
6 2 x 110 1100 2 x 110 kW pumps
Panel 1
Ancillaries 130m from node
6 110 550 Max length of cable from here is
380m
Panel 1 belt drive Node 5 225 1100
Main belt drive Node 2 350 1100
Main drift belt drive Node 1 2 x 225 1100
Panel 2 intake drive conveyor
drive Node 7 350 1100
Cross cut
conveyor drive Node 10 125 1100
Return conveyor drive Node 11 225 1100
Panel 2 return conveyor drive Node 12 350 1100
Panel 2 continuous miner
(return drive) Node 13 500 1100
Panel 2 continuous miner
(intake drive) Node 14 500 1100
Main fan Node 4 300 1100 Axial flow fan
Pump station 50m from node 2 55 550 Mine drainage
(water)