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Process Help ENVSEQ - create extraction sequence for mineable envelopes |
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Process Name |
Menu Path |
Link to Command Table |
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ENVSEQ |
Report ribbon | Model Reserves | Sequence Envelopes |
Introduction
This process will post-process a block model generated from the MODENV process and evaluate the economics of mining satellite ore envelopes taking into account development, access and processing requirements to produce an extraction sequence.
How to use
The MODENV process outputs a grade (or value) model with additional fields *ENVELOPE and *ENVNUM to define the cell classification and each distinct spatial grouping of mined cells based on the optimization criteria:
- maximum ore tonnes (equivalent to minimum included waste or dilution). If several minimum mining units (MMUs) have the same tonnes, then the MMU with the maximum grade is preferred.
- maximum MMU head grade
- maximum MMU contained metal
- maximum accumulated value, where the supplied field is expressed in currency value eg dollar value.
In all cases except (4), the supplied field would be a grade (or equivalent grade for polymetallic deposits) that is handled as a density weighted average.
The MODENV process also outputs a &RESULTS file which summarizes the envelope statistics for tonnage, grade, value, extent and centre of gravity for each combination of envelope number *ENVNUM, cell classification *ENVELOPE and *SHAPZONE. Only the results for *ENVELOPE classification of TOTAL are used in the sequencing.
The mining sequence must take into account development, access and processing requirements. The criteria for ranking the envelope sequence can be selected from the same list of optimization criteria used to generate the MMU envelope, and a different criteria can be used to optimize the sequence.
The costs of sequential development of any satellite orebody from one that is already included in the extraction sequence are calculated from data in the costs penalty &COSTS file. The penalties are a function of the size and relative spatial position of the two MMU envelopes. The file must have a representative number of entries for the field size (SIZE), horizontal distance (HORDIST), vertical distance (VERDIST), and grade/value penalty to interpolate the initial fixed development cost (PENALTY1), and the variable haulage/extraction cost (PENALTY2).
The units of PENALTY1 and PENALTY2 depend on the optimizing criteria used in the the run of ENVSEQ:
- ore tonnes
- grade
- metal content
- accumulated value (eg dollar value)
For example if OPTIMISE=3 (metal content), then PENALTY1 is the metal equivalent for the fixed cost development corresponding to HORDIST and VERDIST distances. PENALTY2 is the metal equivalent per tonne per unit distance for the cost of transporting SIZE units of material over the HORDIST and VERDIST distances.
The envelope separation can be measured by centre of gravity (@DISTMETH=1), or closest distance between the envelope surfaces (@DISTMETH=2). Sufficient values must be included in the &COSTS file to allow the penalties to be interpolated for every combination of envelopes. Every combination of the selected values of SIZE, HORDIST and VERDIST must be included in the &COSTS file, and the file must be sorted in order of increasing SIZE, HORDIST and VERDIST. The penalty applied to an envelope to determine if it can be mined will take into account the PENALTY1 to provide access from the prior envelope, and the cumulative haulage/extraction cost (sum of PENALTY2 values in the sequence).
An envelope sequence file &SEQUENCE is used to predefine sequence relationships between envelopes that the user wants to predefine. Three types of relationships can be defined:
- To specify one or more envelopes that will be developed at the start of the sequence (specify ENVNUM1 and SEQTYPE=1). This option could be used to provide access through multiple shafts.
- To specify that one envelope must be developed from another (specify ENVNUM1, ENVNUM2 and SEQTYPE=2)
- To specify that one envelope must be developed from another but allowing other intermediate envelopes (specify ENVNUM1, ENVNUM2 and SEQTYPE=3)
If a &SEQUENCE file is not defined the process chooses the envelope that has the highest value based on the defined reference point, after penalties have been applied. If no reference point is defined then the envelope with the highest insitu value is chosen as the starting envelope.
The best mining sequence is reported in the &OUT file with pairs of envelope numbers ENVNUM1 and ENVNUM2. The result can be visualized as an inverted tree structure (of parent-child relationships) with any envelope linked back to only one parent envelope. A parent envelope may have more than one child.
Files, Fields and Parameters
Input Files
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Name |
Description |
I/O Status |
Required |
Type |
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ENVMODEL |
Input model file for evaluation. This will have been created as the output &ENVMODEL file by process MODENV. It must have the fields XMORIG, YMORIG, ZMORIG, NX, NY, NZ (implicit) and IJK, XC, YC and ZC (explicit). XINC, YINC and ZINC must exist as either explicit (sub-cells permitted) or implicit (no sub-cells). If it is a Rotated Model then it must also include the fields X0, Y0, Z0, ANGLE1, ANGLE2, ANGLE3, ROTAXIS1, ROTAXIS2, and ROTAXIS3. The file also has the fields *GRADE, *VALUE, *ENVBEST, *DENSITY, *OPTIMISE, *ENVELOPE and *SHAPZONE if specified. The value in the *ENVBEST field depend on the default value of the implicit field *OPTIMISE: 1 - (maximize ore tonnes) then the values in the two fields are ore tonnes. 2 - (maximize grade) then the values in the two fields are grade. 3 - (maximize metal) then the values in the two fields are metal content. 4 - (maximize dollars) then the values in the two fields are dollars. |
Input |
Yes |
Block Model |
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RESULTS |
Input results summary file to report statistics for each envelope, with fields *ENVNUM, *ENVELOPE, *SHAPZONE, *GRADE, *VALUE, VOLUME, TONNES, MINX, MAXX, MINY, MAXY, MINZ, MAXZ, COGX, COGY, COGZ. Each combination of *ENVELOPE (and *SHAPZONE if supplied) is included by MODENV but only those records where *ENVELOPE has the value 'TOTAL' are used in the sequencing. |
Input |
Yes |
Undefined |
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COSTS |
Input file to define the costs associated with alternate sequence combinations. The fields SIZE, HORDIST, VERDIST, PENALTY1, PENALTY2 are required. The file must have all combinations of the discrete values selected for SIZE, HORDIST and VERDIST and be sorted in the same field order. |
Input |
Yes |
Undefined |
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SEQUENCE |
Optional input file to define required sequence relationships between envelopes. Three fields ENVNUM1, ENVNUM2 and SEQTYPE are required. |
Input |
No |
Undefined |
Output Files
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Name |
I/O Status |
Required |
Type |
Description |
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OUT |
Output |
Yes |
Undefined |
Output sequence summary file, with pairs of sequence relationships in ENVNUM1 and ENVNUM2. The initial envelope value IVALUE, the penalty values PENALTY1 and PENALTY2 to the previous envelope, and PENALTY3 for prior envelopes and the final envelope value FVALUE are output. This file will also contain the centre of gravity of each envelope, if @DISTMETH=1, or the coordinates of the closest points, if @DISTMETH=2 stored in the fields (X1,Y1,Z1) and (X2,Y2,Z2). |
Fields
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Name |
Description |
Source |
Required |
Type |
Default |
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GRADE |
Numeric (explicit) field for the grade of input model blocks. |
ENVMODEL |
No |
Numeric |
Undefined |
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VALUE |
Numeric (explicit) field for the value of input model blocks. |
ENVMODEL |
No |
Numeric |
Undefined |
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SHAPZONE |
Field in the input model to distinguish zones. |
ENVMODEL |
No |
Any |
Undefined |
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ENVBEST |
Numeric (explicit) field for the best envelope grade or value in the &ENVMODEL file. |
ENVMODEL |
Yes |
Numeric |
ENVBEST |
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ENVELOPE |
Alphanumeric (explicit) field for the cell envelope code in the &ENVMODEL file. |
ENVMODEL |
Yes |
Character |
ENVELOPE |
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ENVNUM |
Numeric (explicit) field for the envelope number in the &ENVMODEL file. |
ENVMODEL |
No |
Numeric |
ENVNUM |
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DENSITY |
Optional density field in the input model for average grade and tonnage calculations. |
ENVMODEL |
No |
Numeric |
Undefined |
Parameters
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Name |
Description |
Required |
Default |
Range |
Values |
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HDGRADE |
Required head grade for economic envelopes. The definition of head grade depends on the value of @SEQOPT. An absent value will cause the head grade test to be ignored. |
Yes |
Undefined |
Undefined |
Undefined |
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REFZ |
Reference elevation for calculation of penalties for the initial envelope. If a &SEQUENCE file is not defined then the reference elevation would normally be the surface elevation. The coordinate system for defining @REFZ is the unrotated system used in &ENVMODEL. |
No |
Undefined |
Undefined |
Undefined |
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REFX |
Reference X coordinate for calculation of penalties for the initial envelope. If a &SEQUENCE file is not defined then the reference X coordinate would normally be the Easting of the existing or proposed shaft. The coordinate system for defining @REFX is the unrotated system used in &ENVMODEL. If the value is set to absent data (the default) then neither the X or Y reference coordinates are used. |
No |
Undefined |
Undefined |
Undefined |
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REFY |
Reference Y coordinate for calculation of penalties for the initial envelope. If a &SEQUENCE file is not defined then the reference Y coordinate would normally be the Easting of the existing or proposed shaft. The coordinate system for defining @REFY is the unrotated system used in &ENVMODEL. If the value is set to absent data (the default) then neither the X or Y reference coordinates are used. |
No |
Undefined |
Undefined |
Undefined |
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SEQOPT |
Method to be used for ranking the envelope sequence: 0 - Use the same method used for optimizing the &ENVMODEL model. This is recorded as the default value of implicit field OPTIMISE in file &ENVMODEL. 1 - Maximize ore tonnes ie minimize [below cutoff] waste. 2 - Maximize grade 3 - Maximize contained metal 4 - Maximize accumulated value ie for dollar value. |
No |
0 |
0,4 |
0,1,2,3,4 |
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DISTMETH |
Method for defining the envelope separation: 1 - measured by centre of gravity 2 - measured as the closest distance between the envelope surfaces. |
Yes |
1 |
1,2 |
1,2 |
Notes
No additional notes.
Example
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!ENVSEQ |
&ENVMODEL(envmod3),&RESULTS(results3),&COSTS(costs2), |
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&OUT(seq1),*GRADE(NI1),*ENVGRADE(GRADE),*ENVELOPE(ENVELOPE), |
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*ENVNUM(ENVNUM),@HDGRADE=1.2,@REFZ=0.0,@REFX=0.0, |
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@REFY=0.0,@SEQOPT=0.0,@DISTMETH=1.0 |
Error and Warning Messages
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Message |
Description |
Solution |
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