WASTE DUMP DESIGN

Table of Contents

• What You'll Learn • Allcut ramp design • Applying boundary • Dump Volumes by bench • Review

Overview

The new Pit design tools provide a high level of flexibility when performing dump designs.

What You'll Learn

This section will show you how to use the Pit Tools to create a Dump Design and a DTM of that design. We will then generate a Volume report, and a Bench Volume report of material that can be stored on each bench. The software tools used for dump design are the same as those used for the proceeding Pit Design exercise. Many concepts detailed in the Pit Design exercise are not repeated in this exercise. For this reason, the Pit Design exercise must be completed before beginning the Dump Design exercise.

EXERCISE

Objective

We will perform the dump design on the combined surface of the topography and the pit design. These files were combined in the previous section where you created a plot the design. A key objective of this exercise is to show you how to set up an all cut ramp. 1. Open top_clip1.STR . Your screen should display the following image:

2. Open the file dump_base.str into graphics. This will provide us the base of the dump design. This is our outer limit for the stockpile. We need to create a centre lines for the ramp to follow. Using the CREATE | POINTS | ON LINE BETWEEN POINTS, select the first point and the second and to insert the point half way select fraction

Now we will create a line from this point at 90 degrees to create the centre line. Select CREATE | POINTS | BY ANGLE. Select the 1st and 2nd point and create a point 90 degrees from this.

The image shown below will be displayed.

We are now ready to start the dump design. The top of the dump is approximately 50 metres above the topography, at an elevation of 1045 metres. The elevation and gradient of the centre line is irrelevant. The gradient will be set during the dump design process.

4. From the Pit design menu, choose Select slope method. In the Define Slope Method form, choose Design slope.

5. Now we can set the design gradient. Select PIT DESIGN | SET SLOPE GRADIENT and set the design gradient to 38 degrees and angle

The new design gradient will be shown in the status toolbar at the top of the screen

6. DEFINE THE NEW RAMP, but firstly display the point markers so that we can determine where to insert the ramp by Display → Point → Markers. Then select PIT DESIGN | NEW RAMP and select the two points either side of the ramp centre line.

7. Enter the parameters as shown below and choose Apply.

8. After applying the above form, you will be prompted to select the ramp centre line. Select the ramp centre line anywhere on the centre line where there are no other strings, which you may accidentally snap to. (Therefore select the line somewhere along the centre of the segment, not at one end or the other).

After selecting the ramp centre line, the dump top outline is actually modified very slightly as shown in the next image.

This change is made by the software to resolve geometry problems at the start of the ramp.

We will only have one safety berm in this dump at 1025 metres. We have a choice of using Bench Height and designing a 20 metre bench or using `To Elevation' and specifying the elevation. Elevation is simpler as it does not require us to do the mathematics ourselves and also shows a function not used in the pit design exercise. Choose Expand string → To elevation then click on the dump outline. Enter the parameters as shown below and choose Apply.

The projection of the selected string towards the target elevation may result in a design which is unacceptable for the type of mining equipment which will be used.

By entering the Maximum bench height the design may be restricted to ensure that limits are not exceeded. If a bench height limit has no value in your design you can enter a large value such as 9999 or as shown on the previous form if expanding down the value needs to be below the present design elevation thus -999.

The screen will be updated, as shown below.

We will now create a 10 metre berm at this elevation.

9. Under the Pit design menu, choose Expand segment → By berm width, enter the parameters as shown below and choose Apply.

10. Now we will project the dump outline to the DTM of the topographic surface. Choose Load a DTM surface and load TOP1, leaving the display DTM at N.

11. Choose Expand segment → To DTM sureface and enter the parameters as shown below. It is important to change the limiting elevation from 9999 to 0 so that a limiting elevation is not used.

The image shown below will be displayed

Show the DTM offsets to see that the base of the Dump has been extended to match the DTM surface.

12. Save the design to a file called DUMPDESIGN1.STR.