Blast Hole Depth Script | Mining University

Blast Hole Depth Script

When designing a blast, it is important to know how deep each of the blast holes should be. Vulcan has an option in the ‘Drill and Blast’ tools in the ‘Open Pit’ menu, but what do you do if you don’t have this menu? The referenced script will allow the user to identify the distance from the hole collar to a given elevation and output this value to the point name.

I first came up with the idea for this script when we were having trouble controlling the bench level on each bench. The floor of the pit was becoming increasingly uneven and management’s method of solving the problem was to have the survey crew shoot in each collar, calculate the depth to the next bench (plus sub drill) and mark it on the stake for that hole. I didn’t want my friends on the survey crew to take hours out of their day to write elevations on wooden stakes so I put together this little script. Now they print the blast pattern with hole depth and give it to the driller, leaving them with plenty of time to survey working faces for me .

Download the script here:

The script is not totally automated. Before using the lava script you must register your blast hole collars to the current topography. To register the hole collars to a surface triangulation:

  1. Load the surface triangulation and blast hole collars layer into Envisage
  2. Select the menu option Design > Object Edit > Register
  3. Select the collar points by layer
  4. Select a point in the layer and confirm the correct layer
  5. In the ‘String Registration’ panel select the ‘2D Registration’ radio button and the ‘Interpolate’ checkbox
  6. Click ‘OK’
  7. Cancel out of the option 
Now that the collar points have been registered you are ready to run the script. Copy the script into the current working directory.

  1. Select the menu option File > Lava
  2. In the ‘Enter script to run’ panel select the ‘point_rl_ref_rl.lava’ script from the drop down menu
  3. Click ‘OK’
  4. Enter the elevation of the bottom of the drill hole (including sub-drill)
  5. Click ‘OK’
  6. Select the collar points by layer
  7. Select a point in the layer and confirm the correct layer
  8. Cancel out of the option

The hole depth has been written to the point name. To display the point name:

  1. Select the menu option Analyse > Label > Point Label
  2. Select the ‘Name’ radio button and click ‘OK’
  3. Select the collar points by layer
  4. Select a point in the layer and confirm the correct layer
  5. Cancel out of the option
This script isn’t as robust as the options available with the ‘Drill and Blast’ tools but at the time this was written, we didn’t have the module (blasts were just laid out as collar points) and it didn’t seem worth the $5,000 to get the module from Maptek.

The script was a lot of fun to write because it was the first time I really had to format the output. The ‘w’ tag was being used to store additional information so the hole depth was written to the point name. This didn’t seem like a problem except that I couldn’t use any of the label options to limit the number of decimals. Even with the necessity to learn about Perl’s sprintf function, this script only took about 20 minutes to write (it took me longer than that to write this post). I hope that this script saves you at least 20 minutes.

1 comment:

  1. I've been reading up on blasting in Cedar City UT. Apparently I have to have some done, and I'd like to know more about it.