Setting up a Boretrak plan using Shotplan / Setting the right Sample Point Spacing option/ Setting the depths of the holes
Sample Point Spacing is a tool that helps the users setup the their boretrak plan. Strayos provides three different options to help plan the setup of the drilled holes to optimize the powder content and run burden analysis on the bench face.
This tool uses three variables to build the boretrak plan:
- Distance between borepoints: this variable sets the spacing between each borepoint in a drilled hole
- Sample point count: this variable decides on the number of borepoints that will go into each drilled hole
- Toe Plane: Toe plane sets the depth of hole or how deep each hole should be drilled
Sample Point Spacing has three settings. Each setting lets the user set two out of the above three variables mentioned and calculates the third one based on the two inputs made by the user based on:
Number of points * Distance between points = Depth
Option A: Set distance between points from Depth
User enters the spacing needed between the borepoints and defines the toe plane to set the depth of the hole and the app calculates the number of points that will go in
Number of Points = Distance between points / Depth
Option B: Set number of spaced points from Depth
User enters the number of borepoints and defines the toe plane to set the depth of the hole and the app calculates the spacing needed between the points that will go in
Distance between points = Number of Points / Depth
Option C: Set number of sample spaced points from Collar
User enters the spacing needed between the borepoints and number of borepoints and the app calculates the depth of the holes
Depth = Number of points * Distance between points
Q. How to set the Toe Plane Elevation?
The user can manually enter the elevation value in the shotplan editor or select the elevation value of a point on the model by using the option "Select on Model" present in the shotplan editor
Double click the point on the model to select the elevation at the point and the user can see a virtual horizontal plane drawn on the model passing through the point selected.
Q. Subdrill, how is it added to the depth ?
Shotplan editor provides the option to enter the subdrill if any. The subdrill is added to the depth value of the holes and the borepoints drawn below the toe plane for subdrill are indicated by the purple line as shown below:
Understand how depth interval may affect burden calculations
In Shotplan module, the depth interval between borepoints is set to have a default value of 0.5 meters or 2 feet if your account is using Imperial unit. You are allowed to edit the depth interval value before calculating burdens.
The actual meaning of the depth interval means the depth (vertical) distance between borepoints in a shotplan hole. But different intervals sometimes can bring variance in burden calculations.
Strayos algorithm is designed to have more sensitivity in scanning data points with a smaller depth interval, i.e. it will scan more data points at the top of bench if depth interval is smaller. In some cases, it will bring accuracy in top-face area detection. But in some cases, higher sensitivity could be over fitting and bring a negative effect.
In the following screenshots, you can see that 2ft interval has detected more data points on bench top, causing some 3D minimal burden points (blue dots) are detected at top, rather than at face.
How to solve this issue?
If you have noticed some data points are detected on the bench top, here are two ways to solve it:
1. Increase depth intervals : As mentioned above, increase depth interval could scan less data points, make the algorithm focus on bench face rather than bench top.
2. Select ‘Enable backward burden fix’ button before calculate burden. It will add a constraint that only scan the data points in front of holes according to blast direction. Enable backward burden fix is a computation intensive process and takes additional time than usual to generate the reports.