This is a reference document on how to lay out a shot using Strayos without a GPS.
This practice will utilize a burden pole, hole tape, paint, and a drone. This document
serves as a best practice guide. Benches and shot designs will vary from site to site,
adjustments should be made as needed.
Approaching your blast area, with your pattern and hole size known, start by
measuring burden offsets from the toe or crest for each row of your shot. This
measurement can be tailored site by site on backbreak conditions or highwall angle.
Marking three or more profile measurements with your pole and tape at locations along
the bench will provide a visual reference on the 3D model. When these marks are
painted and visible to the drone, it will be easier to reference the AB line annotation in
Strayos. These marks should be painted so they are easily visible to the drone at 200’
(no specific length of marking).
In this example a 4’’ hole is being used, on a 10’ x 10’ pattern, therefore the 3
burden measurements are at 10’, 20’, and 30’ from the toe (10’ of burden 1st row, 20’
burden 2nd row, 30’ burden 3rd row).
Next, once the bench has been flown and a 3D model has been attained on
Strayos, the shot design process can begin.
Strayos will first ask to draw an AB line. This is a guide or reference line for the
length and direction of the shot to begin the layout process. Here, one will draw their AB
line, using the measured markings on the ground as a reference. Using the three
markings painted (visible on 2D/3D models) to draw your AB line along, you will then
input the shot information for your drill design. If your measurements on the ground
are accurate, your rows in the drill design should match up exactly with the painted lines
on the ground seen in the model.
Once designed, you can select individual holes and assess the burden
information for each hole to asses if it matches the criteria you are looking for. In the
image below for hole 7 in row 1, I am looking for 10’ of burden. As shown in the profile, I
have about 12’ of burden when a straight downhole exists. From this information, I can
adjust the hole to meet the optimum burden I am looking for, whether that is adding an
inclination, or adjusting the collar position forward/backward in reference to the AB line.
Again the AB line will be in reference to the markings I have painted on the ground.
When laying out your shot on the bench, you will use the painted markings as a
reference for hole placement. For example, if a hole was adjusted 2’ forward in
Strayos, you will know to measure 2’ forward off your painted reference points. With
angled holes, the same principle applies as you design a hole with an angle, you will
reference the collar position.
Without a GPS, markings painted on the bench for measurement will be the best
way to reference hole locations based on your offsets. Strayos will report your
drill design with distances from the AB line if you have adjusted the hole locations.