Definition: Stemming is the material used to confine the energy of explosive such that the energy does not dissipate vertically. If there were no stemming the energy would find the least resistance path of vertical outlet and cause flyrock and airblast. Optimum stemming length is very site-specific and depends on factor such as the strength of rock, charge diameter, charge energy, Burden, flyrock, water, etc.
Strayos app calculates the stemming info based on the burden and integrates into 3D burden profile report.
1. Stemming in hole profile
In Shotplan design page, select one hole and open ‘View Hole Profile’, the stemming value will be automatically calculated and shown in ‘stemming’ input field.
This default value is calculated from the equation:
default_stemming = 0.75 * max_3D_burdens.
In the example below, the default_stemming = 0.75 * 35.4 = 26.55.
All the depth value at left will be displayed in GREY if they are smaller than 26.55.
It’s possible to manually change the stemming value and see the changes in hole depth.
2. Stemming in 3D visualization
After calculating burden analysis, in the burden report page, you can TOGGLE ON stemming visualization on the top right of 3D map (By default it’s off).
The stemming length will be displayed in WHITE color in 3D view. Sliding the button to adjust the stemming ratio, and stemming length for each hole is calculated from this equation:
stemming_length = stemming_ratio * max_3D_burdens_of ABline
The range of stemming_ratio is from 0.5 to 1.3.
The stemming length of each hole is based on the max burdens of AB Line and the ratio value you selected.
In the above example, we have four rows and two AB lines (two rows at left belong to the first AB line and the other two rows at right belong to the second AB line). We have set the stemming ratio to be 0.62, and the stemming length is calculated and colored in white.
3. Stemming in burden report
Keep the stemming visualization ON and download the burden reports, it will contain the stemming information in the report. All the depth point smaller than the stemming length will be colored to BLACK and in the middle of the drawing, there is a text indicating the stemming length value.
To exclude stemming information from the burden report, just turn off the stemming visualization and directly download burden report.