Clinorule

Mapping in magnetic ore bodies (e.g., sulphides, disseminated base metals) is normally impossible using a magnetic compass. Difficulties may also arise where rock bolts and screens are present as ground support in underground excavations.

In these environments, it is necessary to measure joint orientations using a device called the Clinorule.

Clinorule Description

The Clinorule is a simple device (normally used in carpentry or by underground drillers) consisting of two arms connected at one end by a pivot hinge. On this hinge, there is an angle measure (ranging from 0 to 180 or from 0 to 360 degrees) to record the angle formed by the two hinged arms. It is handy, as well, if one of the arms is fitted with a bubble level along its EDGE. This is to allow accurate measurement of Dip.

Data Measurement

Dip is measured by holding the arm with the level in a horizontal position such that the other arm moves in a vertical plane about the hinge. Move the second arm until it is parallel with the Dip (line of maximum slope) in the joint plane. Read off the (acute) angle as the Dip.

The azimuth direction is taken as a relative angle with respect to a Reference Line. This line is usually the axis of drift of a tunnel, but can be any reference direction which is known (an accurate measure of this reference azimuth should be taken from level plans).

For example, if the Clinorule is used to measure relative Strike, hold one arm of the clinorule so that it is parallel to the Reference Line. Treat this as local "north". Move the other arm (in a horizontal plane) so that it is parallel to the strike line (line in the plane which is horizontal), obeying the RIGHT- or LEFT-HAND RULE as appropriate (be consistent). Read this angle as the apparent Strike.

Data Orientation Convention

The Data Orientation Convention refers to the orientation format of the data collected on a Traverse. For each Spot Mapping discontinuity, the orientation format of the data you enter in the first two columns of the Discontinuities grid (in the Orientation Data dialog), must correspond to the Data Orientation Convention selected.

The following Data Orientation Convention are available:

• Dip/Dip Direction
• Strike(Right)/Dip
• Strike(Left)/Dip
• Trend/Plunge

The Data Orientation Convention option allows you to specify the orientation format for individual Traverses. This allows you to combine different data formats within the same DIPS file.

If the Data Orientation Convention is different from the Reporting Orientation (entered in Project Settings), the raw input orientations will be automatically converted to the equivalent Reporting Orientation.

Traverse Format

The Traverse Format for a Clinorule Traverse is always Trend/Plunge, and is applied as follows:

• The azimuth of the Clinorule REFERENCE LINE (see above) is input in the Orientation Data dialog as the Trend of the Traverse Format. This value is added to the Dip Direction, Strike, or Trend (whichever applicable) of the Discontinuities data measured on the Traverse.
• The Clinorule Traverse is computed the same way as a Linear Scanline Traverse for Terzaghi Weighting bias correction.

Declination

Ensure that the Declination in the Orientation Data dialog is ZERO if Clinorule drift orientations are taken from grid north.

An example DIPS file which uses the Clinorule Traverse Type is the EXAMCLIN.dips8 file, which you should find in the Examples folder in your DIPS installation folder.