Enable/Disable Switchback

On the Mining | Pit Design tab, in the Ramp group: Use the Enable Switchback options to select a road point and mark it so that a switchback is generated from it.

Alternatively, right-click on a Road point in Vizex and select the Road > Switchback > On the Next Bench . The road point will be marked so that a switchback is created to the next bench.

The Switchback tool works by considering the road points on a Toe polygon and determining whether it has been marked by the user to generate a switchback from that point to the next bench. Only the points on a Toe polygon are selectable as road points when generating a switchback.

When a Switchback is enabled, the Selection Assistant will guide you through the selection process:

  1. First, you will be prompted to select a toe, crest. or contour string (if a string has not already been selected prior to clicking on the Turn On button).

    2. Alternatively, you can Digitise the required object/s using the button in the Selection Assistant toolbar. The Selection Assistant will close, providing access to the tools used to create the object.

  1. Then you will be prompted to select a BLUE point as the road point from which the switchback will be generated.

    2. When you have made the selections the following will happen:

    • If Switchback parameters are already defined in the Edit Properties form, a switchback is generated up to the next bench, with the gradient of the haul road corresponding to the parameters defined in the Properties form. Since the switchback extends across the full bench height, a tapered berm is extended along the apex of the switchback.
    • If Switchback parameters are not defined in the Road Properties form, the Properties form is displayed and you must define the following properties of the switchback before it can be generated:

    Curve Radius

    Specify a radius value that will be used to determine the extent and tightness of the curve of the turning area.

    Gradient and Gradient Units

    Specify a gradient value and the Gradient Units.

    Height from start of bench

    Specify the height of the switchback from the start of the bench. This parameter characterises the distance from a bench, from which a road making up a segment begins to change direction.

    Radius Calculation Line

    The radius is measured from a specified (Inner , Centre, Outer, or Custom ) point on the road, taking into account the road width (which is already defined as part of the properties of the road).

    • Inner curve radius must be greater than 0

    • Outer curve radius must be greater than the road width

    • Centre curve radius must be greater than half of the road width

    • To measure the radius from a specific point on the road, select the Custom option and specify a value which is a factor of the road width.

To turn off the Switchback

  1. On the Mining | Pit Design tab, in the Ramp group: Select Disable Switchback to disable Switchback mode.

  1. You will be prompted to select a toe, crest. or contour string (if a string has not already been selected prior to clicking on the Turn Off button)

  1. Next, you will be prompted to select a RED point as a road point for which the switchback will be disabled. As a result, a normal road projection will be generated to the next bench.

    If you attempt to Turn Off the switchback for a point for which the Turn On command has not previously been applied, then the following warning message will appear:

    There are no road points with switchback to select.

    A similar warning message will appear if you try to Turn On the switchback for a point for which the Turn On command has already been applied.

To edit a switchback

On the Mining | Pit Design tab, in the Ramp group: Click Edit Properties to edit the properties of a haul road or ramp. If the road has been marked to be turned, the properties of the switchback are shown in the form.