The block size may be determined to represent an economically viable mining volume, a series of bench elevations or any combination of layout. Blocks may be any size and shape with a single set of requirements:
1. Setting Up The Pick and Choose Model
The process for analyzing the Block Model is as follows:
The menu structure of the software is organized in the same order:
Enter the name and location of the model. If you enter a file that does not exist, the software will ask if you want to create a new one.
2. Defining Pits
Pits are simply names of separate mining areas. Each area has it own set of grid files, even the files are the same throughout the project. All projects must have at least one pit. New models include this pit and assign its name as ‘Default’. Press the “Define Pits” button on the main screen to rename, or add pits. The screen will appear as:
Click on a Pit Name in the list. The name will appear in the bottom entry box. It may be edited there. The pit named DEFAULT may not be renamed unless more than one pit exists.
Press the New button to add a name. A box will appear where the name can be entered for the new pit. When pits are renamed in the bottom box, the change is not recorded until you click on another name in the list. The Cancel button will discard all changes made while on the screen.
3. Specify Model
Set the model file, and the pit on the main screen shown here:
This shows where the model is set to X:\425-002\200407\test, and the pit is set to DEFAULT. Press the Specify Model to obtain a page similar to:
The mining model entry is made in the grid or spreadsheet on the dialog. Mining materials (strata) are defined along the top of the spreadsheet, and attributes (qualities) are listed along the left edge. Every material in the block has the opportunity to relate to every quality. Items that do not apply, are simply left blank in the grid.
Grid or triangulation files may be entered as the defining limits and the qualities of the materials in the blocks. The files are NOT required to be of equal spans, or spacing in grids, and do NOT need to be of similar shape in triangulations. They should, however, cover the entire area of the block model. Blocks falling outside the file limits of a particular area will have that particular volume or quality set to nothing (no data.)
The first pit in the list (DEFAULT or to whatever it has been renamed), defines the material(s) and attached quality(s) associated with each material. All materials (strata) and qualities used in each pit must be defined in the first pit, even if they do not exist. Calculations are made on a regular spacing in the limit of the blocks. This calculation spacing is defined by the user in the box ‘Common Calculation Spacing.’ This box must be filled in on the first pit, before the entry page is saved to the model or the software warns that it is blank.
4. Manual Entry:
The example entered here was ‘burden’ as a strata, and ‘MAG’ as a quality:
5. Entering File Names In The Spreadsheet:
Move the cursor to an appropriate cell in the spreadsheet and
double-click the cell with the mouse. Select the file and press OK.
The file name will appear in the box. Materials are defined as top
and bottom elevations or a series of thickness files. To establish
elevations, the first (top most in the model, left most column in
the spreadsheet) material is required to have a structure, or
elevation file in the box labeled Top Elevation File. The remainder
of materials require only a bottom structure or thickness file.
All materials must be defined the
same way, bottom elevations, or thickness. To toggle between
elevations and thickness files, double-click the left-most
spreadsheet cell, fourth row down. The label will change
“Bot Elevation File” and “Thickness”
Once the spreadsheet is complete, select the File pulldown, Save
and Exit option. Be careful, as
CLOSING THE SCREEN WITH THE X IN THE UPPER RIGHT CORNER OF THE
WINDOW, IS EQUIVALENT TO CANCELING THE ENTRY.
The model has three strata, ls1, ls2, and ls3. The file name values are entered for ls1, but are blank for ls2 and ls3. The common folder path is set to X:\425-002\model\BATDORF. By placing the cursor in any cell under the ls1 heading, and pressing the AutoFill Right button, the software looks for files that have the ‘ls2’ where the ‘ls1’ occurs in the previous files. It repeats the process for each blank cell, under each named strata. Because the files existed in folder X:\425-002\model\BATDORF for this example, the screen now appears as shown below. This example shows the benefit of using consistent naming practices in Carlson.
6. Copying Files From Other Pits
After the model is set up in the first pit, the basics are complete. However, additional pits still need to have reference to appropriate files for those pits. If model files are being entered for a pit other than the first pit, another option is available under the File pulldown menu. It will appear as “Copy From Pit <NAME>” where <NAME> is the name of the first pit in your project. If this button is picked, an exact duplicate is made of the default (first) pit.
If the names of the files are the same as the first pit, but the folder they are in is different, simply copy the first pit files, and change the Common File Folder. If the files exist, they will redisplay. Files that do not exist are shown in red. You may also copy files into the first pit from another block model file if the current model file is newly created. Select the option under the File pulldown, select the database, and the files are filled in.
7. Laying Out Blocks
Block outlines are generally simple a series of boundary lines stacked one on top of the other throughout the reserve. Generally the block height represents a single bench elevation used in the mining. For example, look at the example below of a pit with a ramp, created with the Carlson Process Fill/Cut command, and rendered with the 3D Viewer.
If we look at a plan view of the pit, contoured at the bench elevations, we would see something like the following:
The contour lines at each bench elevation become the limit of blocks we are going to create. Blocks outside those lines are not accessible, and do not require storage in the block model. The software allows each level of stacked blocks to have its own limiting boundary. In the case of a single bench mine, a single boundary line is all that is required.
8. Block Bench Entry:
Set the appropriate pit on the main menu, and press the Layout Benches And Blocks Button. The screen will appear similar to:
The buttons in the top left corner control the zoom level and view by Zooming Out, In, Previous, Extents, Window, and Pan, respectively.
Block definition is divided into two portions. The first option is Definition of Block Base Elevations. The second option is the Definition of Block Boundaries.
Block Elevation boundaries (Benches) can be accomplished by two methods:
Manual Entry Block Base Elevations
Step 1:
Enter low, high, and spacing (step) values of benches in the upper
right boxes. Pressing the Add button places the values in the frame
labeled Bench Base Elevations To Use. For example, suppose the
bottom of the pits were at elevation 1240 with bench elevations of
40 units extending upwards to the highest bench of 1520. With those
values in the appropriate boxes, pressing the Add button results
in:
The list of elevations now shows in the Bench Base Elevations To Use frame, sorted highest to lowest. Each has a color attached to help differentiate the boundaries. To enter a single elevation into the list, put the single elevation value in the Hi, and Lo box, with a Step =1, and press the Add button. As many as required may be entered. The values do NOT need to be equally spaced.
Step 2:
Once all the elevations are set for the benches, each must be
assigned a limiting boundary line. Click the mouse on one of the
elevations. The elevation will turn bold. In the example below,
elevation 1520 was selected:
The bottom button in the Bench Base Elevations frame now says “Set 1520 Inclusion Perimeter” Press that button to select the boundary line in AutoCAD. Once selected, the screen will reappear. In this case the outer-most boundary line from the contours shown earlier was selected and the screen returns:
Repeat Step 2 for Each boundary line until the screen appears similar to:
Note that the selected elevation in the list highlights the
appropriate boundary line on the drawing.
Automatic Entry of
Block Base Elevations
If the limiting lines for each bench are already drawn on a single
layer in AutoCAD, and are 3D Polylines, or 2D Polylines with
elevations (as drawn by the Process Fill/Cut command, or Contouring
routines in Carlson), the software can use them automatically. The
button labeled Select Bench Elevs By Layer In DWG accomplishes this
task. Pressing that button switches to the AutoCAD drawing and
prompts the user to select a single entity. Note: All entities on
that AutoCAD layer are examined so the boundary lines should reside
on a layer to themselves (no other polylines on the layer). When
the selection is made, the following prompt will occur:
Selecting Yes causes all elevations to be added to the list automatically, and the polylines attached. Choosing No causes only the elevations to be added to the list (no boundary lines.) In this case, Yes was selected. Press the Zoom Extents button to see the boundaries.
Definition of
Block Boundaries
Regular Blocks
Block boundaries are defined in with the options in the lower right
box on the page. The simplest option is the button “Regular Block
From Starting Point And Angle.” The option creates
rectangular shaped block boundaries based on a selected
orientation. When this option is selected, the screen switches to
AutoCAD.
The pit layout screen reappears prompting for the length and width of the block faces. The software then draws the blocks on the screen that could possibly be present. The following screen is an example where square blocks were selected:
As the screen above indicates, some of the blocks are outside the perimeter, some are inside, and some are partially in, partially out. This shows the need for some method to decide whether the block is included in the model or not.
The box labeled “Minimum Block % To Include In Calcs” allows the user to enter a threshold for using the block or not. A value of 100 would include only blocks completely inside the perimeter(s) of the elevation benches while a value of 1 would include any block inside or touching the perimeters. Regardless of the value entered, the percentage of each block contained inside the perimeter is stored along with the block model. When the blocks are mined, the percentage is applied to the recoverable volumes and weight.
Arbitrary Blocks
The following is the perimeter of the example Inside Of AutoCAD. It
has a series of interior lines drawn at pit boundaries (blue ends
indicate the grips from selection in the drawing):
The arbitrary block algorithm uses a polygon processor logic to create the polygon block boundaries from primitive lines and polylines.
Regardless of the option, the software starts with the prompt:
Coordinate snap is a method to force the selected line segments to intersect, or trim as needed automatically. It helps clean up loosely drawn geometry to create perfectly matched polygon edges. The following demonstrates the affects of coordinate snap:
Any small number is acceptable, depending on the integrity of the primitives selected. If gaps and overhangs occur in the drawing larger than the entered snap, the user is warned. Red circles are also drawn in the AutoCAD drawing where the errors exist to aid in correcting the primitives. Assuming Option 1 is selected, and the lines shown in the last diagram are selected in AutoCAD, the screen will return as:
Depending on the complexity of the geometry, a small amount of time may pass as the software build the polygons.
Saving The Block Boundaries And
Elevation Limits:
Process To File, and Process And Append To File accomplish the same
task, building the block model. Process To File erases any existing
definitions of blocks for this pit, rewriting them completely. The
Process and Append leaves existing blocks, adding the new ones
described in the page. A progress bar appears on the screen to
indicate progress. The process run time is completely dependent on
the total number of block, total number of elevations
(benches), and the complexity of the geometry. This process
of building blocks is required for each pit separately.
9. Building The Model
This section is fully automatic after setting the active pit and pressing the Build Model on the main screen. Optionally, you may use the File pulldown menu >Build All Pit Models. This option runs the model for each pit, one at a time. The routine interpolates each structure and quality file in the model at the common resolution, applies them to each block, and summarizes the block in the model. It is the most computer intensive section of the block model program.
All summaries are kept in the model file itself. For example, if the model is name Test, the summaries are all in the disk file Test.mdb The software also creates a series of model files for each pit. If we had three pits defined, three additional files would be made: Test1.mdl, Test2.mdl, and Test3.mdl. These files can be quite large depending on the detail of the user selections. However, they are quite useful in analyzing the model (next section.) The software uses the files to instantly re-analyze blocks, should you choose to split a block on elevation boundaries.
Updating A Model With New
Information
As is generally the case, continuing mining activities yield more
and more information. Should additional holes be drilled, or pit
samples added to the Carlson model, the user may choose to rebuild
the grid or TIN files used by the model. If that is the case, and
the changes warrant updating the blocks, building the model is a
simple as pressing the Build Model button.
However, this is true only if the model names are unchanged, and the block layouts have not changed. Those changes require re-entry of the applicable data before building the model.
10. Analysis
After the model is built, press the Analyze Model button on the main page. The screen appears similar to this:
Using The Screen
Basic Concepts:
Selecting Blocks (Blocks are selected in multiple ways):
De-Selecting Blocks:
Previewing The Block Data Before Selection:
If a single block is selected with the right mouse key, a detail of the block is displayed as shown here:
As the mouse is moved throughout the block, the detail data is shown in the spreadsheet in the lower left. That data reflect the values where the mouse lays in the block on the drawing. The total block data is shown in the right spreadsheet. The Exit button cancels the selection, and the OK button adds the block to the temporary list. (Optionally the block seams to mine, or the elevation to mine to is set as explained in later sections.)
Real-Time Block Data
Feedback:
As the mouse is moved the text under the drawing gives basic
feedback on the block. The data shows the bottom elevation of the
topmost un-mined block the mouse is over. It also shows the group
of the last mining that occurred in the block above.
Locating Selected
Blocks:
After blocks are selected, they may seem difficult to locate. So,
the spreadsheet has some special actions that allow you to find a
block on the drawing.
The highlight remains on until another block is selected.
Changing Analysis Screen Appearance
The data visibility can be set with the pulldown menu View> Set Quality Visibility. The following grid appears to turn particular data on/off:
The left side of the screen allows you to set the number of colors, and the red, green, blue components of the good, bad, and mid-range colors. The right side of the screen allows selection of the qualities to consider. Turning on the checkbox activates that quality in the weighting. The Weight For This Quality box allows the user to weight a particular quality greater or lower than others in the analysis. The value has no application for a single quality. The Hi Numbers Are Good check box allows the user to specify whether the best value of the quality is a high or low number. The following is an example of the result with 2 qualities, equally weighted. Gray blocks are areas with no quality information to weight.
The primary quality is selected in the top box. In this case, MGO was selected. Then a series of breaks was entered into the top spreadsheet. The example shows 3, 4, 5, and 9999999. This would equate to zones of : 0-3, 3-4, 4-5, 5 and up. When the cursor is on a particular row, slide the Red, Green And Blue sliders to obtain a color. Double click in the preview color box under the sliders to set that color to that row.
The secondary quality will be used (if included) to set shades of colors between the two primary colors ranges. Set the applicable seams (materials or strata) and press OK. Each block will be displayed in its own color, for the weighted total of the selected materials.
Limiting Mining In Blocks:
Note: When a block is partially mined, and added to a group, the remainder of the block is still present for selection in the drawing. For example, if we mine two block, one to elevation 1460, and one through the ‘Waste’ seam. The drawing would appear as:
This text is only visible when the drawing is zoomed to a fairly tight scale. The next time we choose that block, the material mined previously will be not be shown, because it has already been removed from the block
Double-click any title to make the group the current group, and to edit its name in the lower box, or press the new button to add a new group and name it. When the OK button is pressed, the current group data is displayed. When a group is displayed, the drawing zooms to the group limits, and draws a yellow boundary line around the group such as:
The check box at the top of each column includes or excludes the column from the total column. (The box must be changed and the cell exited before the totals update). The data can also be exported to Microsoft Excel with the Send to Excel option.
Pulldown Menu Location:
Block Model
Keyboard Command:
csbm