The Strayos burden analysis tools calculate the 2D and 3D minimum burdens for each point at 0.5m intervals down the hole.
3D minimum burdens: For each borehole point, the app looks through all the model surface points to find closest one in a 3D spherical range. The minimum burden is calculated as the distance between these points. To visualize this, at a plan view the 3D burden shown in each of the bounds for each face hole.
2D burdens: For each borehole point, 2D burdens are calculated by finding the closest model surface point at the same elevation and in a direction specified by the 'Burden Azimuth'. There are three options for setting the Burden Azimuth using the 'Burden direction' dropdown in the Edit Hole popup:
- Auto - The azimuth will be calculated as the direction which has the least average burden for the hole. This is useful for corner holes as it will show automatically show 2D burden in the direction with lightest burden.
- Row Direction - The azimuth will be set to be perpendicular to the row
- Manual - You can edit the Burden Azimuth field to see the 2D burdens in your preferred direction
Reading the profile chart in the app
- The red line represents the hole
- The grey line represents the 2D burden profile of the face
- The red numbers on the left side of the chart indicate the depth interval. These will be grey if they are below the "Stemming" length entered
- The blue numbers show the 3D minimum burden at each depth interval. These will be purple if below the "Threshold" entered
- The yellow points with grey numbers show the 2D burden for each depth interval. These will also be purple if below the "Threshold" entered
Reading the chart on the Burden Report
The chart is read the same way as described above with several additional pieces of information
- The hole is color-coded based on the 3D minimum burden as shown in the legend in the bottom right corner
- The blue dotted lines show the path of between each borehole point and the 3D minimum burden point on the model surface. Note: these may not lie exactly on the 2D profile line as they may be in a different azimuth.
- The 2D burden values will appear along the solid line which indicates the open face. The values are labeled with small dotted yellow circles.
- The coloration in the table can be adjusted by the user, by inputting threshold values. Anything below the threshold will appear red, while values exceeding the threshold will appear blue. This is to indicate inadequate burden vs excessive burden in the 2D and 3D table of values.
The min burden will also be shown in the profile, and can be adjusted to ignore stemming length (function see above where thresholds can be adjusted in left hand toolbar). In the profile above, the minimum burden is show at a depth of 2 feet with a minimum value of 6 feet. After adjusting the "Ignore Stem" length to 6 feet, we now see the profile showing the minimum burden of 7.8 feet at a depth of 7.1 feet.