Charging parameters
To run this function: Choose Design > Ring design > Setup > Charging parameters, or...
Charging Method
There are two methods of determining the length of charge in a hole. These are the traditional Critical radius method, in which each hole is charged from the toe back to the first point that is inside a specified radius of an existing charge and the AECI algorithm. The AECI algorithm is slightly more complex:
In contrast to the existing critical radius method whose results are very dependent on the order in which the blast holes are selected for charging, the AECI algorithm guarantees consistent results when processing a group of holes. The benefit of the AECI algorithm is that blast holes can be processed as a group without requiring individual blast hole selections to take place.
Note that the AECI algorithm processes holes in clockwise order around the opening. Consequently there is no need to select the order of charging as is required with the critical radius algorithm. However this also means that the CHARGE HOLES function only uses the Critical radius charging method.
The AECI algorithm is described below.
To describe the AECI algorithm the following key is used:
- S - represents a Short stemming length which is 20 x hole diameter
- M - represents a Medium stemming length which is 50 x hole diameter
- L - represents a Long stemming length which is 120 x hole diameter
The stemming length for blast holes is determined using this pattern, processing holes in clockwise order around the opening.
S M S M S M ...
That is
(short stemming length)
(medium stemming length)
(short stemming length)
(medium stemming length)
... etc.
An exception to this charging pattern occurs when a blast hole is encountered that has a length that is greater than 1.5 x L. When such a hole is found, the charging pattern using stemming lengths in accordance with the pattern below:
S L M L S L M L ... This pattern repeats until the next blast hole to be charged is shorter than 1.5 x L. The charging pattern then reverts to the original pattern of:
S M S M ...
The selected charging method is used in the following functions:
Critical radius
When using Charge Holes or the Critical radius charging method, the critical radius ensures that no part of a hole will be charged if it lies within the critical radius of an existing charge.
Stemming
The length of hole at the collar which must remain uncharged when using the Critical radius charging method.
Minimum charge length
If a calculated charge is shorter than this specified minimum, the charge will not be created and a warning message will be reported.
Hole colour
The colour of holes which cannot be edited in DRILLING. These holes may be from a ring other than the current ring, or surveyed as being not in the current ring plane. These holes can be charged and the charges are considered during charging of new holes.
Explosive
The name of the explosive to use during charging. The names and specific gravities of the explosives can be edited by selecting EXPLOSIVES from the Charging submenu.
Choose Apply to save the changes made to the charging parameters for the duration of the current Ring Design session. To save the parameters for future sessions, run SAVE RING DEFAULTS.