Reserve Calculation Techniques
Using Benching and Batters - Bench Grid Creation
Grid Calc Macro: DEMOBENCHES.GDC_CMND
This Grid Calc macro creates a set of mining bench grids, mid-bench grids and bench thickness grids.
! Filename: demobenches.gdc_cmnd ! ! ! ! Part 1. Generate Overburden Bench Surfaces ! ! This macro generates the bench surface roofs for all Overburden Benches. ! Overburden benches are defined as OB2.SR (Base) then +/-n50. The OB2 ! bench grid was designed and used as the basis for overburden bench ! modelling. ! Naming as: demoob2.srg Base Overburden Bench ! demoob1.srg (demoob2.srg - 50) Overburden Bench 1 ! demoob3.srg (demoob2.srg + 50) Overburden Bench 3 ! --- and so on +/- 50 for all Overburden Benches to Bench 7. ! ! Note Each overburden bench will be defined by its crest grid, ie, OB2 ! overburden has a crest grid named- "demoob2.srg". The toe grid is the ! crest grid of the horizon below, ie, "demoob1.srg". For the OB3 bench, the ! crest grid is called "demoob3.srg"; the toe grid for OB3 is called ! "demoob2.srg", and so on. ! ! demoob2.srg is the original design Grid !!!! access_specs/area="ALL"/access_specs EDIT/EQUATION=ob2.sr-50 EDIT/EQUATION=max(z,a.sr) save ob1.sr EDIT/EQUATION=ob2.sr+50 save ob3.sr EDIT/EQUATION=ob3.sr+50 save ob4.sr EDIT/EQUATION=ob4.sr+50 save ob5.sr EDIT/EQUATION=ob5.sr+50 save ob6.sr EDIT/EQUATION=ob6.sr+50 save ob7.sr closegrids ! ! Part 2. Generate Overburden Bench Thickness Grids ! ! Subtract the Top surface from the Base surface to give the OB bench thickness. ! First: Take the Minimum of topo.tp and bench.sr ! Second: Take the maximum of "z-bench below.sr" & "0" (zero) ! Thirdly: Mask the grid where thickness = 0 ! Lastly: Save as bench.tk ! EDIT/EQUATION=min(topo.tp,ob1.sr) EDIT/EQUATION=max(z-a.sr,0) EDIT z+0*mask(z gt 0) save ob1.tk EDIT/EQUATION=min(topo.tp,ob2.sr) EDIT/EQUATION=max(z-ob1.sr,0) EDIT z+0*mask(z gt 0) save ob2.tk EDIT/EQUATION=min(topo.tp,ob3.sr) EDIT/EQUATION=max(z-ob2.sr,0) EDIT z+0*mask(z gt 0) save ob3.tk EDIT/EQUATION=min(topo.tp,ob4.sr) EDIT/EQUATION=max(z-ob3.sr,0) EDIT z+0*mask(z gt 0) save ob4.tk EDIT/EQUATION=min(topo.tp,ob5.sr) EDIT/EQUATION=max(z-ob4.sr,0) EDIT z+0*mask(z gt 0) save ob5.tk EDIT/EQUATION=min(topo.tp,ob6.sr) EDIT/EQUATION=max(z-ob5.sr,0) EDIT z+0*mask(z gt 0) save ob6.tk EDIT/EQUATION=min(topo.tp,ob7.sr) EDIT/EQUATION=max(z-ob6.sr,0) EDIT z+0*mask(z gt 0) save ob7.tk EDIT/EQUATION=max(topo.tp-ob7.sr,0) EDIT z+0*mask(z gt 0) save ob8.tk ! ! Part 3. Generate the Split Coal Horizon Grids. ! The B Seam is split according to mining constraints: ! B1 Seam is >= 5 feet and <= 65 feet thick. ! B2 Seam is >= 5 feet thick. ! ! First: Generate the B1 Seam SR, SF, and TK. ! B1.SR = B.SR ! B1.SF = Max(B.SR-65,B.SF+5) ! B1.TK = B1.SR-B1.SF ! ! Second: Generate the B2 Seam SR, SF, and TK. ! B2.SR = B1.SF ! B2.SF = B.SF ! B2.TK = B2.SR-B2.SF ! ! Third: Generate the B1 Midburden (Parting) thickness grid. ! B1P.TK=B1.MD = A.SF-B1.SR ! ! Fourth: Generate the A seam thickness grid ! A.TK = A.SR - A.SF ! ! FIRST EDIT/EQUATION=b.sr save b1.sr EDIT/EQUATION=b.sf+5 EDIT/EQUATION=max(b1.sr-65,z) EDIT/EQUATION=min(z,b1.sr) save b1.sf EDIT/EQUATION=b1.sr-b1.sf save b1.tk ! SECOND EDIT/EQUATION=b1.sf save b2.sr EDIT/EQUATION=b.sf save b2.sf EDIT/EQUATION=b2.sr-b2.sf save b2.tk ! THIRD EDIT/EQUATION=a.sf-b1.sr save b1.md EDIT/EQUATION=b1.md save b1p.tk ! FOURTH EDIT/EQUATION=a.sr-a.sf save a.tk
