Surface Mine Reserves
Function
This command calculates quantities and qualities from drillholes or
predefined grid or block models.
Strip ratios can also be calculated as the volume of non-key strata
divided by the tons of key strata. Key strata
are intended to be the target ore, and non-key strata are intended to
be the overburden, interburden and parting strata.
Within the drillholes or PreCalc file, each strata has a field that
specifies whether the strata is key or non-key. Volumes can be stored
in the pits for scheduling with this command. There are many options
for reserve calculation and they are detailed in order of appearance
below.
- Modeling Method: The
surface reserves can be generated on-the-fly from the selected
drillholes or read from
stored grid files put into a PreCalc file. The on-the-fly modeling
method can be either
Triangulation, Inverse
Distance, Kriging, Polynomial or Linear Least Squares. An explanation
of these different methods is found under Make Strata Grid Files. The
Block Model option is available for licenses that have the Hardrock/Ore
Module installed. It creates a BLK block model file and calculates
reserves "on-the-fly". The
stored grid
file method is the
Pre-Calculated option. The Pre-Calculated modeling method uses prepared
grid files that represent the
bottom elevation or thickness and quality attributes (i.e. BTU) of the
strata. The
grid files associated with each
strata and the ground surface are set in the Define Pre-Calculated
Grids command under Drillhole.
- Source of Top Surface Model...: Surface
Mine Reserves works from the top strata down to the bottom.
The ground surface
is modeled from either the Screen using selected surface entities, the
surface grid found in the PreCalc file, a separate grid file (something
different than the surface grid in the PreCalc, such as a top of bench
grid) or an elevation. This elevation could be the elevation of a flat
bench that represents the top of the reserve calculation interval. In
the Screen method, the program builds a grid model from the
selected entities (contour
polylines, points and 3D entities). See the Make 3D Grid File command
for a
description of creating a grid file.
The "Source of Top Surface Model" option sets this ground surface
method. Each strata structure is
modeled as the bottom elevation of that strata. The strata volume is
figured by comparing the strata
bottom elevation model with the previous strata. The first strata
bottom elevation is compared with
the ground surface grid. Each strata grid clips to the grid above so
that the strata grid does not
rise above the previous grid which includes the ground surface. The
result is that the program will
find strata outcrops if any.
- Top Elev: When using the
Elevation method in the Source of Top Surface Model, this is the
elevation that controls the top of the structure or reserve block.
Enter in any elevation.
- Source of Bottom Surface
Model...: Carlson can either calculate quantities straight
down from the
inclusion polylines
("Cookie-Cutter") or apply side slopes. There are two methods for
modeling the side slopes: using a bottom surface grid or highwall
slopes (explained below). Without either of these methods, the
program will calculate the
strata quantities straight down vertically from the inclusion
perimeter. In all
cases, the strata quantities
are limited by the ground surface grid or elevation which effects the
top strata and
outcrops any other strata.
The Strata Model option will calculate down to the lowest grid in the
PreCalc, or the lowest grid in the Selected Strata option, if that is
used. The Grid File method will go down to this grid for reserve
calculations. It can have any number of benches and slopes in it. This
method will prompt you for a grid file which
should represent the bottom of pit surface including the side
slopes. This grid file should have the same position and resolution as
the surface grid. Keep in mind
that the grid resolution should be small enough to model the pit side
slopes. For example, a 100 ft
grid interval would not work well for modeling side slopes that are 30
ft wide. Instead, use a
grid resolution that is smaller than the side slopes width (i.e. 10 ft in
this example). There are
many routines for preparing the pit bottom grid including the
Design Bench Pit routine and Make 3D Grid File. Typically the inclusion
perimeters should
start from the daylight line where the pit bottom grid intersects
the surface grid. The program will calculate the strata quantities
between the surface grid or elevation and the pit
bottom grids. The last option is Elevation. It allows for entering an
elevation to represent the base of the reserve "block". If using
Elevation for the Top Surface Model, and Elevation for the Bottom
Surface Model, it will calculate the various quantities within the two
elevations that could represent benches. Shown below is an example of
the Source of Bottom Surface Model as a Grid File.
- Bottom Elev: When
using the Elevation method in the Source of Bottom Surface Model,
this is the elevation that controls the bottom of the structure or
reserve block. Enter in
any elevation.
- Use Surface History: This
option will use the series of grids
stored in a
grid sequence file (.GSQ) for bench volume calculations. The first grid
in the file is used as the
starting surface grid and the second grid is
used as the bottom grid. The program calculates the strata quantities
and qualities using these
two grids. Then the program repeats this time using the second grid as
the surface grid and the
third grid as the bottom grid. Again the strata values are calculated
using the next two grids.
This process repeats until the last pair of grids in the sequence file.
The purpose of this routine is
to calculate the strata values at different mining stages or benches.
These benches are reported separately in the final report. One routine
that prepares the grid
sequence file is Design Bench Pit. If the Store Results in Pits is
selected, these benches are automatically assigned to the pits for
timing.
- Use Highwall Slopes:
This method applies the side slopes
on-the-fly. The slopes to use
are specified under the Set Slopes button. In this
method, the inclusion perimeters should go around the base
of the pit. The program will apply the side slopes from
the inclusion perimeter up to the surface starting at
the elevation of the bottom strata. The daylight
perimeter and any bench lines are drawn as 3D polylines. This will only
use depths up from the bottom for benches. If more complex benching is
needed, then the Use Surface History is the preferred method.
- Set Slopes: When using
the Highwall Slopes option, this button brings up the Highwall Slopes
dialog. Slope can be entered in as Percent or Ratio. The Smooth Slope
Transitions is "all or nothing". using the slopes shown, if the depth
was 60, then the entire slope would be 1.5:1. The Slopes in Series
option is more for benching. Using the slopes shown below, 0-50 will
always be 1:1. Once the depth gets above 50, it will switch to a 1.5:1
and so on. Using Slopes in Series will allow for Repeat Slopes, until
it gets up to the surface. There are only 5 different rows available to
enter in the slope template.
- Use Drillhole Elevations in
Surface: This option only applies if one of the modeling
methods are chosen and not Pre-Calculated. The drillhole surface
elevations should be used if they enhance the surface topo, but if they
differ from the surface contours or points, then they should not be
used.
- Ignore Zero Elevations: This
option only applies when using the entities on screen to create the
surface. Unless the mine is down near sea-level, zero elevations should
normally be ignored.
- Use Triangulation
Subdivision: This option only applies to the modeling
methods of Triangulation and Polynomial. It subdivides the triangles to
create smoother surfaces and ensure that contours do not cross.
- Use Global Trend Extrapolation:
This also applies only to Triangulation and Polynomial. This option
finds the average
slope and direction of the existing data and applies this slope to
extrapolating where there is not surface data. .
- Output Elevation Grids:
Turning this option on will create grid files for the bottom of each
strata found in the drillholes. Each grid needs to be named separately.
The command Make Strata Grids is a better way to create these grids.
- Output Thickness Grids:
Turning this option on will create thickness grids of the strata
calculated for the current bench. It will prompt to create an
overburden thickness grid, a key thickness grid and a key tons grid
(tons/sq ft. or m). These grids will also be stored in the pits, if
Store Results in Pits is activated. The difference is that timing using
the actual numbers will
average the quantities over pit area while the grids will model the
thickness within the pit so that timing through a shallow end of the
pit will be faster than the deep end.
Within Output Thickness Grids, there is an option to divide the bench
by
thickness. This option will
split the non-key volume at the specified thickness into two benches.
For example, if you have 50
feet of overburden and one piece of equipment will remove the first 10
feet
while a second removes the rest,
then set the divide value at 10 feet and it will divide the first
overburden into two benches.
- Recovery Percent: This
window defines the percentage of Key strata volume that was recovered
in mining and to include in the volume and strip ratio reporting.
The non-recovered key strata is added to the NonKey volume. The
recovery
percent in the Surface Mine Reserves dialog applies to all the Key
strata. Enter in as 100 or 95.4 or 92, etc.
- Use Strata Definitions (for
Recovery): To have different
recoveries for each Key strata,
use Define Strata to create a strata definition for each Key strata
with the appropriate
recovery percent. Then run Surface Mine Reserves and click on Use
Strata
Definitions.
- Use Attribute (for Recovery): Another
recovery method is to have a strata attribute for recovery. This allows
for different recovery percents
at different drillholes. Then the recovery is modeled for the area. The
name of the
recovery attribute is specified in the dialog. This attribute will need
to appear in the drillholes for modeling on the fly, or in the PreCalc
as a strata attribute, with the name spelled as it appears in the Name
window to the right.
- Name (Attribute): This
is the name of the recovery attribute that will be referenced when
using the Use Attribute option for recovery percentage.
- Min Key Thickness To Use:
This option adds key
strata to the nonkey strata above, in areas that
have thickness less than the specified minimum thickness. Also areas
with thickness less than
the minimum are not counted in the reported strata area.
- Use Density Attribute:
The strata density can be defined at different levels from
general to specific and the
program will use the most specific density that is found for the
strata. The most general density setting
comes from the current drillhole definition file (.ch) as set with the
Define Drillhole command. The next
level is the density setting that is stored in each drillhole. To check
a drillhole density, use the
Edit Drillhole command, the Key density is displayed in the bottom of
the dialog. The next level is strata specific density that
can be assigned with the
Define Strata command. The most specific level of density definition is
the
"Use Density Attribute" option shown here in Surface Mine Reserves.
This
option models the strata density using the strata attribute
with the user-specified name for density (i.e.. "Density"). Not only does
this method use the
modeled strata density when averaging the strata quantities with other
strata, but the modeled density
is used within the strata to weight average that strata qualities. For
example, if the strata is more
dense in one area, then the qualities such as BTU in this area with be
weighted more heavily. This can be changed if desired, under Attribute
Options in the Report Formatter.
- Name (Density): This is
the name of the Density attribute that will be referenced when using
the Use Density Attribute option for recovery percentage. This
must be spelled exactly as it appears in the drillholes or PreCalc
file.
- Min Minable Parting Thickness: This setting
will add the non-key parting quantities with the
key quantities when the non-key parting thickness is less than
the specified
amount. For example, if the
Min Minable Parting is set to 0.5, then a non-key strata between two
key strata would be
combined with the key in areas where the non-key thickness is less than
0.5 feet. In areas where
the thickness is greater than 0.5, the non-key quantities are not
adjusted. Combining the
non-key quantities to the key will add to the total key tons and affect
the strip ratio. If the non-key
strata has qualities (i.e. ASH, Sulfur), then these non-key qualities
will be composited by nonkey tons
with the key tons for the portion of non-key that is less than the
minimum
parting. This will
dilute the key qualities.
- Which Strata To Include...: This
determines what will be calculated for the reserve. If All is chosen,
then all strata in the drillholes or PreCalc file will be calculated
and reported. If Selected is chosen, then the next window to appear is
where one or multiple strata can be selected. This can be used for
multiple reserve runs, selecting different strata to represent each
bench.
- Skip Running Totals:
This option skips the running total quantities and strip ratios
for the strata. If if is not selected, then the total for each pit is
added to the next for a "running total" quantity. If it is checked,
then the pits are totaled separately, and with a grand total at the end
of the report.
- Report Areas On One Row:
This option puts all the strata quantities
and qualities for each pit polyline on one row.
This format is best suited for only a few strata and for printing
landscape on a page. If it is not selected, then each strata will
appear on a separate row.
- Calculate Strata Qualities:
This toggle will report
the
average qualities for strata attributes
such as BTU and sulfur. Otherwise the program skips calculating
qualities to save time. Besides
reporting the qualities for each strata individually, the program can
also report the total averaged
qualities. By default, the qualities are weight averaged by tons which
are
calculated by using the strata volume
and density.
- Breakout Quantities By
Attributes:
This feature works in conjunction with the Block Modeling feature in
the
Ore Module. Only users who have
purchased the Ore module can utilize this option. Once the BLK file
has been
created, and the grade parameter file defined, they are used in this
reserve routine
to calculate the volume of material falling in certain ranges.
For example, Surface Reserves will report tons of ore with calcium of
80-90, tons of ore with calcium 90-100, etc.
- Fixed Non-Key Qualities: This
option will prompt to enter
one value for each strata quality found in the drillholes or PreCalc
to use for all non-key strata. This option is useful in the case for
calculating the composite key
strata qualities when there is key strata dilution from non-key strata
due to Min Minable Parting. Prompts will look like:
Non-Key value for BTU: 1000
Non-Key value for MOIST: 35
Non-Key value for SUL: 7
Non-Key value for ASH: 50
Non-Key value for DENSITY <80.00>: 155
- Use Named Pit Areas:
The area for calculating quantities defaults to the limits of the
selected surface entities
and drillholes if no inclusion perimeters are selected. To control the
calculation area, multiple closed
polylines for areas to include
and/or exclude can be selected. An unnamed pit polyline will limit the
area of calculations. Also, areas can be labeled with site
and pit names (i.e. Site 1, Pits
101, 102, ...). Surface Mine Reserves will then calculate the strip
ratios and volumes for each site
and pit area. To use site and pit names, there are several commands for
creating named pit polylines in
the Boundary menu of Advanced Mining. If this is selected, then it will
look just for named pit polylines, ignoring anything else.
- Store Results In Pits:
This option is available
when named pit polylines are used. This option will store
the total non-key volume, key volume and key tons and all quality
attributes for
each pit polyline as extended entity data to the pit
polylines. These quantities can then be used by the
Surface Equipment Timing command. Besides the quantity and quality
values, a Bench number is also stored with the quantities for
sequencing each bench. For example, if you
have two key and nonkey seams that you are going to mine in two
passes, then use the Which Strata to Include: Selected option
and choose the
first
pair of NonKey/Key strata with the Bench# set
to 1. Then run Surface Mine Reserves a second time with the second pair
of NonKey/Key strata and the Bench# set to 2. The quantities calculated
can be stored either as values or as thickness grids for scheduling.
The grid option is activated by the Output Thickness Grids option,
otherwise it will store the values in the pits. The
difference is that timing using the actual numbers will
average the quantities over pit area while the grids will model the
thickness within the pit so that timing through a shallow end of the
pit will be faster than the deep end.
Within Output Thickness Grids, there is an option to divide the bench
by
thickness. This option will
split the non-key volume at the specified thickness into two benches.
For example, if you have 50
feet of overburden and one piece of equipment will remove the first 10
feet
while a second removes the rest,
then set the divide value at 10 feet and it will divide the first
overburden into two benches.
- Bench #: Enter in the
Bench number to assign for this "run" of Surface Reserves. Usually
Selected Strata is used with this, to select the strata to assign for
each bench number reserve run.
- Use Property Boundaries: Property
boundaries can be used to break up the reserve by owner and property.
The commands for laying out property boundaries are in the Boundary
menu. Essentially,
property boundaries are closed polylines with owner and property ID
names. The property polylines
do not need to be clipped with the calculation inclusion perimeter or
pit polylines. The program
will internally clip the properties with the calculation areas and
report the amounts by property
within each pit area. If a pit or inclusion polyline is not covered by
a
property, the property name
used for these quantities is "unknown". To activate property
boundaries, click on the
Use Property Boundaries toggle and the program will search and find
them automatically.
- Strip Ratio Output: The
Draw Contours option will contour the total
strip ratios of all the processed strata (NonKey volume : Key tons).
The program will create the
contours from a grid file of the calculated strip ratio values. If you
just want the grid file and not the contours, choose the Grid File
toggle and
the program will prompt for a grid file name to create.
- Type of Strip Ratio Output: There
are two
methods for making the strip
ratio grid and contours. The Instantaneous option will calculate the
strip ratio
using the strata thicknesses of
the vertical strata column at each grid corner. The Accumulative method
will start with the lowest
strip ratio in the calculation area and keep adding the next best strip
ratio areas, basically an accumulative strip ratio of the selected
areas of the mine site. The grid file is
assigned the running strip ratio as the program adds these areas.
- Min Depth To Use: The
Minimum Depth to Use option adds key strata to the overburden
in areas that have depth less than the specified
minimum depth. For example, if any Key strata are closer than 10 feet
to the surface, then they can be considered "weathered" and reported
with the NonKey waste material.
- Non-Key Thickness To Add To
Key:
Above Key/Below Key: These fields allow you to specify the
amount of non-key thickness above
and/or below the key strata that will be combined with the key (roof
and floor dilution) This
amount will be taken from the
non-key quantities and added to the key. Similar to the Min Minable
Parting Thickness, the
non-key quantities will increase the total key tons which affects the
strip ratio and key volume mined. Also any non-key
strata qualities will be combined by thickness, weighted by NonKey
density, and added to the key which
dilutes the key qualities. For
example, if you estimate that 0.25 feet on average of the overburden is
taken with the coal, then you
could set the Non-Key to Add to Key for Above to 0.25.
The Report Formatter Options dialog is the final step of the Surface
Reserves routine. It is documented elsewhere in the manual for more
details on its operation.
Prompts
Surface Mine Reserves dialog
Select surface entities and at least 3 drillholes. (Unless
using a PreCalc.)
Select objects: select the drillhole symbols and surface
entities. Surface entities can include points, lines, and
polylines.
Select the Inclusion perimeter polylines and ENTER for none:
Select objects: select the
polylines or named pit polylines. The area within these polylines
will be included in
the calculations. They must be closed polylines.
Select the Exclusion perimeter polylines and ENTER for none:
Select objects: select the
polylines. The area within these polylines will be excluded from
the calculations. They must be closed polylines.
Make Grid File Set grid resolution
Triangulating points ... 49
Pass> 6 NULL Z values left> 0
Processing cell 2500 ...
Finished strata Y2
The above four steps are repeated for each strata.
Report Formatter
Pulldown Menu Location: StrataCalc in Advanced Mining and Mining
Keyboard Command: mtntop
File Names: \lsp\mtntop.lsp, \lsp\makegrid.arx, \lsp\makegrid.dcl