Case Study #8, Part 2: Computing Tonnage and Acreage

Application

Once the mine map is completed using the techniques described in the previous section, quantities of mined mineral and waste rock may be computed, with industry standard reports. The reports will be generated based on the reporting method selected in the Mining Settings under Settings, Carlson Configure dropdown menu.

Procedure

1. Configure the "look" of your coal sections (or other mineral).
2. Locate all coal sections measured in the mines.
3. Compute tonnages by average or modeled grid methods.
4. Draw and compute quantities for pillar cuts on the "retreat".

(1) Configuring the Section Information
Configuring the section information involves assigning each strata a name and a density, and specifying the look of the section for when it is placed in the drawing. This information is stored in a user-specified file and is referenced for locating sections in the drawing and for quantity calculations. If you reconfigure an existing section file, sections placed in the drawing using the previous section file become invalid and must be replaced. The strata in a section can be configured as either individual or composite. With the individual configuration, each strata has its own name and density. With composites, each strata is still named separately but they also are divided into groups that have a group name and density. The principle advantage to composites is that it allows you to enter and list out each strata height and then combine the strata into their corresponding composite category when generating tonnage quantities. First, let's configure an individual section. Select Configure Section Info in the Works dropdown.

Now let's make a composite section. Select Configure Section Info in the Works dropdown.

The following figure shows how this section will appear in the drawing.

(2) Locating Sections
To locate section information measured from the mine, select Place Coal Sections from the Works dropdown. Select the desired section configuration file such as SECTION2 which you defined in the previous section.

Now enter your measurements.

Enter the other section as shown in the next figure.

Placing a section

(3) Compute tonnages by average or modeled grid methods
There are three routines for calculating tonnages: Quantities by Average Method, Quantities by Grid Method and Quantities by Centerline. These methods require section sample points, and pillars and a perimeter defined as closed polylines in the PILLARS and PERIM layers respectively. As its name suggests, the average method uses the average values from sample section points to compute its quantities. The grid method actually models the values of the sample points over the mined area which results in more accurate tonnages. For now, let's use the average method because it is much faster and requires fewer sample points.

Select Quantities by Average Method in the Works dropdown.

            Select a Mining Project Definition (MPD) File or Create a new one
            Select the file that defines the section sample points
            Specify the Beginning and Ending dates of take-up and Report Format in the dialog below

          Select property polylines or press Enter for none: press Enter if no property lines defined, if defined program gets Owner Name from here
          Fill in the Following Dialog: if any field is left blank it will not be reported

Quantities by Average Method

A report would be generated based on the Report Format method. If standard method selected following report would be generated

Update coal tonnage files (<Y>/N)? Y  This option updates data files for tonnage reports.
Enter a mine name: Mine
Enter a panel name: press Enter for none
Enter the estimated coal reserves for mine Mine: 300000

(4) Draw and compute volumes for pillar cuts on retreat
One of the final steps in underground mining is cutting into the pillars on the "retreat". The results of these cuts can be quickly drawn on the mine map using the Pillar Cut routine in the Works dropdown. The procedure is simply to pick a cut pattern and then place the pattern inside the pillar to be cut. That's it. Depending on the selected method, this routine will either redraw the pillar's polyline with the cuts removed, or it will create new perimeter polylines inside the pillar in the cut out spaces. The pillars must be closed polylines in the PILLARS layer. The rotation of the placed pattern will follow the current snap. If the cut pattern you need is not already in the table, you can define your own by first drawing a polyline of your pattern and then selecting the user-defined box in the Pillar Cut symbol table.

After redrawing the cut pillars with Pillar Cut, Quantities by Average Method or Quantities by Grid Method can be used to compute the quantities of the cuts. If the Cut option of Pillar Cut was used, then you will get the total quantities from the area between the pillars plus the pillar cuts. To get the quantities of only the pillar cuts, use the Perim option of Pillar Cut. This will create perimeter polylines inside the pillars. Then use Quantities by Average Method and select all these perimeter polylines. Let's practice pillar cuts.

Locating a pillar cut pattern

Select Pillar Cut from the Works dropdown.

Choose the Cut 14 symbol or the symbol of your choice.

Now let's get the quantity mined from the pillar cuts.

Select Quantities by Average Method in the Mining Works dropdown. Choose Section2 or the file that defines the section sample points.

This creates the following plot.

Pillar cut quantities