Edit Layers Window

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Edit Layers

A Layer is the material between two Terrain Inner Surfaces. Layers may represent coal seams, ore bodies or any other material of interest. This dialog box accesses Layer settings.

Layer Name

Name of Layer whose settings are to be modified.

1st Inner Surface

This combo box allows the user to select a first inner surface limiting the selected layer. Below this field minimum and maximum heights of the selected inner surface are shown.

2nd Inner Surface

This combo box allows the user to select a second inner surface limiting the selected layer. Below this field minimum and maximum heights of the selected inner surface are shown.

Layer specific gravity.

Swelled specific gravity

Layer swell factor

The specific gravity of layer material is its density relative to water. Layer material is assumed to increase in volume (i.e. swell) after excavation. So there are two values of specific gravity for layer material:

•In-situ or bank specific gravity (termed layer specific gravity), and

•Swelled or excavated specific gravity (termed swelled specific gravity)

The relative increase in volume after excavation (i.e. situ density/excavated density) is termed the layer swell factor. The three values above are related by:

Layer specific gravity = Swelled specific gravity x Layer swell factor

Entering any one of these values in the dialog box causes one of the remaining two to be recalculated with the other held constant. This is expressed in the following table:

By using this table, the best order to enter these values may be determined.

Render on Terrain

This check box allows showing the areas where the selected layer is exposed on the terrain surface. Such layer traces become visible in Terrain Graphics Windows only in rendering mode.

Layer Color

The base color for rendering the areas of the selected layer exposed on the terrain surface. These appear in Terrain Graphics Windows only in rendering mode.

Offset (Top)

This parameter is used for display purposes only. It does not affect the "actual" top surface position. This parameter is added to the layer’s top surface, so that positive values of this parameter move the apparent position of the top surface up.

This parameter may be used for two purposes:

•To combat numerical imprecision in the render display of a layer on the terrain surface.

Explanation:

If the terrain is excavated exactly to the top surface of a layer, it is not clear whether the excavated area should be rendered as terrain material or layer material. Suppose we want this case to show the excavated surface as layer material. This is achieved by adding a small quantity (say 5cm, up to 30cm in extreme cases) to the top surface heights for display purposes only. In this way it is guaranteed that the terrain surface lies within the layer when the terrain is excavated exactly to the layer’s top surface. Differences in terrain and top surface models (e.g. grid step) can increase the optimal value of this parameter in some cases.

•To thicken thin layers so that they can be more readily seen, for example thin coals seams.

This may be useful for display in steep excavated sections of the terrain. An example is thin coal seams in a high-wall.

Offset (Bottom)

This parameter is used for display purposes only. It does not affect the "actual" bottom surface position. This parameter is added to the layer’s bottom surface, so that positive values of this parameter move the apparent position of the bottom surface up.

This parameter may be used for two purposes:

•To combat numerical imprecision in the render display of a layer on the terrain surface.

Explanation:

If the terrain is excavated exactly to the bottom surface of a layer, it is not clear whether the excavated area should be rendered as terrain material or layer material. Suppose we want this case to show the excavated surface as terrain material. This is achieved by adding a small quantity (say 5cm, up to 30cm in extreme cases) to the bottom surface heights for display purposes only. In this way it is guaranteed that the terrain surface lies outside the layer when the terrain is excavated exactly to the layer’s bottom surface. Differences in terrain and bottom surface models (e.g. grid step) can increase the optimal value of this parameter in some cases.

•To thicken thin layers so that they can be more readily seen. (Negative parameter values)

This may be useful for display in steep excavated sections of the terrain. An example is thin coal seams in a high-wall. In these cases a negative value of offset may be called for, to move the bottom surface down.

Excavated Material Log

Log Material

Selecting this option will store the volumes and masses of layer material removed after each excavation. This information is written to one of the existing Layer Logs.

Excavate Layer

If Layer is excavated, its top surface and (maybe) bottom surface will be changed to the new terrain in the excavated area.

Log Name

This option allows the user to select a Layer Log in which to store the volumes and masses of the selected layer’s material removed after each excavation. A new Layer Log may be created through the menu option Material/Logged Information.

Log Used In

List of all other layers already using the selected Layer Log. After saving current parameters (by pressing the Save Button or closing the dialog box) the current Layer Name will appear in the list.

Close Button

Closes the Edit Layers dialog box after prompting to save current settings (if the Save Button has not been pressed).

New Button

Creates a new layer based on one of the already existing ones (user choice).

Delete Button

Deletes the selected layer.

Save Button

Saves all changed settings for the selected layer. Using this button will prevent the "prompt to save" question when changing layers or closing the dialog box after changing a layer’s parameters.