SVY2302 Mine surveying
Assignment 1
The following table provides an indicative relationship between the course objectives and course assessments. The table should be used as a guide only.
Course Objectives 1 2 3 4 5 6
Assignment 1 v v
Assignment 2 v
Exam v v v v v v
Blasting and Borehole Surveying Problems
Due Date: Monday 12th April 2021
Value: 20% - 200 marks
Note: Scans of hand written assignments will not be accepted.
Students need show all calculation steps. It is acceptable to use calculator close program in the calculations.
Operational Overview
Bandi Bandi Coal Mine is looking to begin a new strip mine from a previously dug box cut and ramp. The first strip is to be dug with the following coordinates:
Point Easting Northing Location
1 389181.562 6947111.891 Sth West Corner
2 389479.379 6947075.721 Sth East Corner
3 389487.207 6947145.282 Nth East Corner
4 389189.39 6947181.452 Nth West Corner
Being a small operation, you, the Mine Surveyor of the operation, have been tasked to calculate the total overburden and coal to be mined within the eastern block of the first strip.
To assist with your calculations 3 various types of boreholes have been drilled. Each of the boreholes have been vertically drilled using rotary percussion and diamond core methods. The relevant geological and downhole survey information relevant to the strip design are as follows:
Borehole
Number Easting Northing Collar RL Depth to Coal Roof Depth to Coal Floor
BH904 389175.32 6947230.679 227.437 59.345 68.821
RH107 389167.675 6947000.435 221.564 59.765 68.453
DDH1245 389655.811 6947090.721 229.056 59.982 69.112
This is a simple design and ratio calculation to ensure that the strip is economic to mine from this location. Due to the nature of your department all calculations and checks must be supplied when submitting your design, volumes, and assessment of the designed open cut pit.
Further information required:
1. 0.3m top soil over to be removed and stockpiled for future rehabilitation over the mining area.
2. 17m of soft mudstone and siltstone pre-srtip will to be removed by truck and excavator prior to drill and blast of the sandstone overburden.
The strip’s overburden will be blasted in one entire cast blast. 2 track mounted drills consisting of 165mm diameter drill bits will be used to drill the all holes on the shot. The blast hoes will be stopped 1m above the coal seam to ensure the roof of the coal is left intact allowing for a good clean up once the coal is uncovered.
The operation uses ANFO across the whole site – approx. 1050kg/m³ for sandstone material. All holes will be drilled vertically.
Question 1 (145 marks)
You will be required to:
a) Calculate the strike and true dip of the Natural Surface, Coal Roof and Coal Floor.
(60 marks)
b) Calculate the Natural Surface reduced levels of the four corners of the strip design.
(35 marks)
c) Calculate the depth and thickness of the coal at the four corners of the strip design.
(30 marks)
d) Calculate the volume of Top Soil, Pre-strip and Overburden to be mined.
(15 marks)
e) Calculate the volume of Coal to be mined.
(5 marks)
Hints:
• Calculate all information for the boreholes.
• Calculate all the information for the designed strip.
• Calculate reduced level information for each mining horizon - where required.
• Draw diagrams for each aspect of the calculation process.
• Complete independent checks where possible.
• Show your full workings for each of the questions.
Question 2 (55 marks)
You will be required to:
a) Design the drill pattern required for the strip.
(35 marks)
b) Calculate the total explosives required for the blast.
(10 marks)
c) Ensure the required explosives will fit in the holes.
(10 marks)
Hints:
• Draw a plan of the proposed blast design at a suitable scale.
• Calculate the average depth of the blast holes.
• Calculate the burden and spacing – will they fit into the dimension of the strip? If not, then adjust the dimensions to suit.
• Calculate the quantity of explosives required.
• Check if the quantity of explosives will fit in the hole.