Edit Pit

Edit Pit allows you to review and edit the quantities and attributes stored in each pit which are used for scheduling in the Surface Equipment Timing and Pit Scheduler commands.

Storing Data in Pits

Quantities and attributes may be stored in the pits using the Surface Mine Reserves, Assign Timing Grids, or Import Pit Timing Data commands (explained below). These values are stored in the pits as Extended Entity Data (EED), along with the pit name and the mining direction. In the pits themselves, some pit data (key tonnage, key thickness, and non-key thickness) may be stored as discrete values or as grid files. The primary difference between these methods is in how Surface Equipment Timing will use the information for scheduling. When data is stored in the pit as a discrete value, it is assumed that the pit is homogenous in regards to that value. When data is stored as a grid file, the value can be treated as variable across the pit. For example, if the OB Volume is represented with a discrete value, it is assumed that the overburden thickness is the same across the entire pit. When mining through the pit, one side of the pit will be mined just as quickly as the other side. If the OB Volume is represented with a grid, however, the true thickness of the overburden will be taken into account during scheduling. This will show how one side of the pit may be mined more quickly/slowly than another side of the pit due to a change in overburden thickness.

The Surface Mine Reserves command provides an option to Use Named Pit Polylines and to Store Results in Pits. These options will store all relevant quantities and attributes in the pit on a specific bench as discrete values. Surface Mine Reserves also has an option to Output Thickness Grids. When this option is used, the thickness grids will be stored in the pits in place of the respective discrete values. If the pit needs to be divided into multiple benches, the values for each bench may be calculated simultaneously with the use of the Use Auto-Run option.
The Assign Timing Grids command will prompt you for three grids to assign to each bench: a non-key thickness grid, a key thickness grid, and a key tons grid. The key tons grid should represent tons/square foot or tonnes/square meter.
The Import Pit Timing Data command will import pit information from a .csv file.

For more information regarding these three commands, see the section of the help manual corresponding to each command.

Edit Pit Dialog

When executing this command, you will be prompted to pick inside a pit polyline. The selected pit will be hatched with a yellow fill and the Edit Pit dialog will appear. If two pit polylines overlap in the location you select, one pit polyline will be highlighted and you will be prompted if the selection is correct. If the program does not detect any named, directional pits with stored quantities, the command will not execute.

Tree View:
The below dialog shows the tree view for a typical pit. In this view, all benches in the pit are listed in the Pit Benches tree view on the left side of the dialog. The information relating to the selected bench will be shown under Bench Details on the right side of the dialog. Most of the values listed under Bench Details may be edited by simply typing a value in the cell of interest or by clicking the File/Edit button to the right of the cell. Precedence rules for the selected bench are shown in the bottom left corner of the dialog.

Spread View:
The below dialog dialog shows the spread view for a typical pit. This view is simply a different way of viewing the pit information shown in the tree view and may be accessed by clicking the Spread View tab near the top of the dialog. In this view, benches are displayed in a spreadsheet for easier side-by-side comparison.

Pit Name and Site Name: These fields set the name of the pit.

Attribute Group: This dropdown menu sets the attribute group for the pit. Attribute groups may be used to assign attribute values/grids to many pits at one time. New Attribute Groups may be defined in the Timing Project Manager.

Bench: This field displays the bench number.

Name: This field displays the full bench name. This is a concatenation of the Pit Name, the Bench Name, and the Bench Number separated by hyphens.

OB Volume: This value sets the volume of non-key material (overburden) in the bench. This value can also be represented by a thickness grid of the non-key material.

OB Shift Volume: This value displays the volume of non-key material that has been shifted into the current bench from another bench. Non-key material may be shifted between benches with the use of the Shift OB Volume button at the bottom of the dialog.

Key Volume: This value sets the volume of key material in the bench. This value can also be represented by a thickness grid of the key material.

Key Tons: This value sets the tonnage of key material in the bench. This value can also be represented by a grid of tons/square foot or tonnes/square meter.

Difficulty: This value sets the difficulty factor associated with the bench. The difficulty factor temporarily modifies the equipment mining rate set in the Timing Project Manager. The adjusted mining rate is the quotient of the original mining rate and the difficulty factor. A difficulty factor of 1.0, or if the difficulty factor is not specified, will maintain the original mining rate. A difficulty factor of 2.0 will double the amount of time required to mine the bench (original mining rate is divided by 2.0). A difficulty factor of 0.5 will half the amount of time required to mine the bench (original mining rate is divided by 0.5). To quickly calculate the difficulty factor, you may want to use the Difficulty Calculator at the bottom of the dialog. The difficulty factor may also be represented by a grid file.

Here it is important to note the difficulty value set in this dialog may be overridden according to a 4-level hierarchy.

The manual entry of the value or grid file set here is at the bottom of the hierarchy.
The second level is specifying the difficulty within an Attribute Group in the Timing Project Manager. There, an attribute named DIFF_BENCH* (where * is a bench number) may also be represented by a discrete value or a grid file. When this DIFF_BENCH* attribute is added to the attribute group, it will actually create a new attribute in the pit itself called DIFF.
The DIFF attribute in the pit is the third level in the hierarchy. This allows you to use a generic difficulty for the entire attribute group, but still manually set the difficultly for individual benches.
The fourth and highest level in the hierarchy is layerized text in the drawing. The text should be the difficulty factor (no prefixes or suffixes) and should placed on a layer named DIFF_BENCH* (where * is a bench number). For example, if the text "1.2" on the DIFF_BENCH1 layer is placed inside a pit polyline, the difficulty factor for the first bench in that pit will be set to 1.2. This difficulty factor will override all others.

Start Date: This field sets the earliest start date for the pit. This can be used to prevent mining an area due to waiting for permit approval, waiting to finalize the purchase of new land, etc. Most of the time this field will be left blank, however.

Key Thickness: This value displays the average key thickness of the bench.

Non-Key Thickness: This value displays the average non-key thickness of the bench.

Area: These values display the area of the bench.

Centroid X and Centroid Y: These values display the coordinates of the geometric center of the pit.

Other Attributes: The bottom of the Bench Details list leaves spaces for a variety of other attributes. Most of these attributes are used to define qualities of the bench. For example, if a bench contains an attribute for Moisture, this attribute will apply to the entire bench. If two strata are added to the same bench, this Moisture attribute will relate to both strata. If you are storing values in the pits using Surface Mine Reserves, the weight-averaging of the attribute will be applied automatically based on the volume and the density of the material. Here it is important to note that the weight averaging of attributes will not account for null values. For example, if Strata A has a Moisture attribute of 0.3, but Strata B does not have a Moisture attribute defined, then the combined Moisture content for the two stratum will be 0.3. To properly weight attributes, it is necessary to define an attribute value for each strata.

Some attributes may be shown with a _NK suffix. This suffix will be applied to differentiate between key attributes and non-key attributes. For example, if Strata A is key and has a Sulfur value of 0.1 and Strata B is non-key and has a Sulfur value of 0.15, these two Sulfur values will be handled separately. The Sulfur value for Strata A will be stored as "Sulfur" with a value of 0.1 whereas the Sulfur value for Strata B will be stored as "Sulfur_NK" with a value of 0.15.

Some attributes may be in the form of XXXX_VOL_FACTOR or XXXX_TON_FACTOR where XXXX is a strata name. This is used to define ratios of material when more than one key strata or more than one non-key strata are added to the same bench. For example, if strata A and B are both key strata, an attribute for B_TON_FACTOR will be shown in the list. If this value is 0.4, then 40% of the key tonnage in the bench comes from strata B. If the attribute A_VOL_FACTOR is 0.56, then 56% of the key volume comes from strata A.

Precedence: This section of the dialog controls precedence rules for scheduling. The precedence list is simply a list of other benches that need to be mined before the current bench can be mined. Basic top-down precedence rules will be automatically entered to prevent mining a lower bench before the upper bench has been mined.

Edit: This button will open a list of all other benches found in the drawing, as shown below. Selecting benches of interest and clicking OK will add the benches to the precedence list. Multiple benches may be selected by clicking and dragging in the list or by holding the CTRL key while clicking.

Remove: This button will remove the highlighted bench from the precedence list.

Screen Pick: This button will allow you to add benches to the precedence list by picking them in the drawing. As soon as you click inside a pit polyline, the uppermost bench for that pit will be added to the precedence list. Clicking in the pit polyline multiple times will add lower benches.

Add Attribute: This button will add a new row to the Attributes list.

Remove Attribute: This button will remove the currently selected attribute from the Attribute list.

Keyword Help: This button will open the list of keyword attributes, as shown below. These keyword attributes may also be added to an Attribute Group in the Timing Project Manager. When an attribute with the _BENCH* suffix (where * is a bench number) is added to the Timing Project Manager, it will also appear in the Edit Pit dialog. Manually editing the value in the Edit Pit dialog will override the value set in the Attribute Group. Attributes that are added to the Attribute Group that do no have the _BENCH* suffix, however, will not appear in the Edit Pit dialog. Note that some of these keywords are only intended for use with the Underground Mining Module. For more information on the specifics of each keyword, see the section of the help manual corresponding to the Timing Project Manager.

Double clicking one of the keywords in the above dialog will add it to the Attributes list on a new row.

Difficulty Calculator: This button will open the difficulty calculator as shown below. This dialog will calculate the difficulty factor based on an increase/decrease in the mining rate and a percentage of rehandle. For example, if the mining rate is expected to increase by 50% and 10% of the material will need to be rehandled, the calculated difficulty factor will be 0.733.

Shift OB Volume: This button will open the Shift OB Volume dialog as shown below. This will move non-key volume from one bench to another. This dialog will not allow you to move more material than what exists in the source bench.

Pulldown Menu Location: Surface Mining Module > Boundary
Keyboard Command: editpit
Related Commands: Surface Mine Reserves, Timing Project Manager, Surface Equipment Timing