About ...Moly-Cop Tools, Version 2.0About the Multistage Flowsheets_SABC-1 Spreadsheet ...

&L&"Arial,Bold"&8Moly-Cop Tools&"Arial,Regular" / &F&R&8&D / &TScope :

The Multistage Flowsheets_SABC-1 spreadsheet was designed to simulate the overall response of a double stage grinding circuit comprising a SAG mill, ball mills, pebbles crushing and feed preclassification options, operating under the so-called SABC-1 configuration; i. e. crushed pebbles are recycled back to the SAG mill.

Theoretical Framework :

The simulator was structured by simply linking into the current file, single unit simulators like SAGSim_Recycle, BallSim_Reverse and ScreenSim_Single. Further, in order to estimate grinding media consumption rates, the spreadsheets Media Charge_Wear&Impact_SAG Mills and Media Charge_Wear_Ball Mills were also linked into the current file.

To overcome the need for a more complex Crusher Simulator, it was decided to simply define their product size distribution as a constant (user specified), regardless of the feed size and tonnage to the crushers.

Data Input :

Most of the data input is done through the attached Control Panel worksheet. Some complementary information (such as Ore Breakage Parameters) is to be input in the respective Data_Files. Make sure all these files contain the correct information for the simulation in place.

To balance the Ball Mills simulation (i. e., set W36 = 0), use the predefined Excel subroutine Tools/Solver ... Notice that the Cyclones Apex Diameter is specified as a restriction in this subroutine.

Simulation results are summarized in SAG_Reports and BM_Reports worksheets. Also, selected simulation outputs are displayed directly on the Control Panel worksheet.

Control PanelMoly-Cop Tools TM (Version 2.0)1000ton/hr, Fresh FeedSABC-1 Circuit SimulatorMesh #1131488F80Opening3048002.90% MoistureSimulation N0By-Pass0.000RemarksD50/Ds1.001Base Case Examplem100.00Upper0ton/hrSplit1.00Mesh #11Ore Density, ton/m32.80Opening304800Lower0ton/hrBy-Pass0.0000.00% of Feed369ton/hrD50/Ds1.002.90% Moisture36.91% of Feedm100.002.90% Moisture1000ton/hr (all mills)40.00% Solids61.50% - 1/2"61.50% - 1/2"80.46% - 100#144.8P802F80131488% - 1.5"58.970.000BpcWater, m3/hr344# of Cyclones4.00213d50cDiameter26.000.322BpfL/DEff. Diameter, ft35.30GrateScreenHeight78.000.339Bpw0.42Eff. Lenght, ft15.00510Mesh #Inlet10.00Speed, % Critical78.007620013335OpeningVortex10.0074.31% SolidsCharge Level, %26.000.0700.017By-PassApex5.00Balls Filling, %10.000.700.90D50/DCirc.% Solids (slurry)76.003.004.00m% - 200# inpsi9.97Load, %App. Density, ton/m33.331% Solids72.79Mill Discharge(Guess)2.224Gross kW10093% - 100#21.2634.27(Actual)2.224kWh/ton10.09T806112(Delta)0.000m3/hr731Size DistributionsMeshOpeningFreshCrushedCrushed48Water,FeedPebbles 1Pebbles 2m3/hr112"304800100.00100.00100.00m3/hr, Water51528"20320097.60100.00100.002.00# of Mills36"15240083.93100.00100.0019.00Eff. Diameter, ftL/D44.15"10160073.57100.00100.00BALL CONSUMPTION24.00Eff. Lenght, ft1.2652.95"7620067.87100.00100.00SAGBall76.00Speed, % Critical62.1"5080062.82100.00100.00MillMills38.00Charge Level, %71.48"3810058.97100.00100.00% Utilization92.092.038.00Balls Filling, %81.05"2667053.7898.0798.07Ball Size127.076.0mm% Solids58.6972.00% Solids (slurry)90.742"1885049.7890.2490.24Scrap Size76.212.5mmm3/hr17105.395App. Density, ton/m3100.525"1333542.7461.5061.50Liner Design4631Gross kW110.371"942338.3248.0448.04# Lifter Bars36389.26kWh/ton123668034.0031.8431.84Lifter Height10.003.00inches134469929.2823.5523.55Lifter Face Angle30.010.0()146332725.6518.0818.08Ball Quality158236222.5714.3214.32kdE3.0001.500mm/(kWh/ton)1610165120.1911.5311.53DBT Performance1714116818.169.209.20Total # of Drops2000010000182083316.797.807.80# Balls in Tube2424PROCESS RESTRICTIONS192858915.656.656.65# Broken Balls55CurrentMin/MaxRemarks203541714.665.745.74SAG Power, kW1009311500OK214829513.795.065.06Consumption Rates (*)Pebbles, ton/hr369400OK226520812.844.434.43gr/tongr/kWhgr/tongr/kWhBM Power, kW46315000OK2310014712.013.963.96Wear541.353.63567.761.29Product Size, P80144.8185.0OK2415010411.123.503.50Breaks10.21.0273.07.88Pump Capacity, P*Q1704730000OK252007410.283.103.10Total551.554.64640.769.17Total Water, m3/hr14702000OK(*) Details in SAG and BM Wear Data_Files.

12Top Screen Opening: Specify a Screen # from the list contained in Cells B41:B65.Bottom Screen Opening: Specify a Screen # from the list contained in Cells B41:B65.Split = 1 = OpenSplit = 0 = ClosedDischarge Grate Opening: Specify a Screen # from the list contained in Cells B41:B65.Trommel or Screen Opening: Specify a Screen # from the list contained in Cells B41:B65.Vortex Diameter: Specified as a restriction in Subroutine SOLVER.To validate the simulation, this cell must be set to 0 by executing the predefined SOLVER Subroutine.

SAG_Data_FileMoly-Cop Tools TM (Version 2.0)SAGSIM_Recycle : Semiautogenous Grinding Mill SimulatorCircuit TypePebbles Crushing and Recycle(see Flowsheet)Simulation N0RemarksBase Case Example0Power, KWMill Dimensions and Operating Conditions4986BallsEff. DiameterEff. LengthSpeedChargeBallsInterstitialLift2882Rocksftft% CriticalFilling,%Filling,%Filling,%Angle, ()1417Slurry35.315.078.026.010.065.046.09286Net Totalrpm10.068.00% Losses10093Gross Total% Solids in Mill Slurry76.00ChargeCharge Weight, tonsApp. Dens.Ore Density, ton/m32.80Volume, m3BallsRocksSlurryton/m3Slurry Density, ton/m31.955108.29193.68111.9655.053.331Balls Density, ton/m37.75Feed Moisture, %2.9Maximum Grate Transport CapacityMesh #% OpenOpen# of GrateArea /Rate Const.Grate Opening, mm76.205AreaArea, in2ElementsElement1/in2/minScreen Opening, mm13.341015.002113936587.210.000Slurry Top Size, mm26.678'Grinding Kinetics Controlled'Specific Grate Area DemandFresh Feedrate, ton/hr1000.0in2/(ton/hr) of Pebbles57.27Min27.50Sp. Energy, KWH/ton10.09in2/(m3/hr) of Slurry24.50Min4.23CrushedFeed Size DistributionPebblesiMeshOpeningMid-Sizeton/hr% Retained% Passing% Passing112"304800100.00100.0028"20320024886824.002.4097.60100.0036"152400175976136.7013.6783.93100.0044.15"101600124434103.6010.3673.57100.0052.95"762008798857.005.7067.87100.0062.1"508006221750.505.0562.82100.0071.48"381004399438.503.8558.97100.0081.05"266703187751.905.1953.7898.0790.742"188502242240.004.0049.7890.24100.525"133351585470.407.0442.7461.50110.371"94231121044.204.4238.3248.041236680793443.204.3234.0031.841344699560347.204.7229.2823.551463327395436.303.6325.6518.081582362280330.803.0822.5714.3216101651197523.802.3820.1911.5317141168138920.302.0318.169.20182083398613.701.3716.797.80192858970011.401.1415.656.6520354174969.900.9914.665.7421482953518.700.8713.795.0622652082489.500.9512.844.43231001471758.300.8312.013.96241501041248.900.8911.123.502520074888.400.8410.283.1026-20000102.8010.280.00% SolidsSelection Function Parameters :100.00Balls onRocks onSelfGrate Parameters :ParticlesParticlesBreakageDefaultalpha00.000992040.000595220.00003245650.7055761603Inefficiency0.0700.4alpha10.6500.6500.743D50/DGrate0.7000.7alpha22.0002.000m3.0003.0dcrit2667016002Breakage Function Parameters :Screen Parameters :Defaultbeta000.300beta010.100(default : 0.0)Inefficiency0.0170.2beta10.450D50/DScreen0.9000.9beta22.500m4.0004.0beta300.12700beta311.000(default : 1.0)Incr. Specific Energy, KWH/ton :3.70(default : 0.2)Pebbles Recycle Ratio :0.37

&L&"Arial,Bold"&8Moly-Cop Tools&"Arial,Regular" / &F&R&8&D / &TThe top Mesh Opening must always be defined to allow 100% of the material passing through such screen.The top Mesh Opening must always be defined to allow 100% of the material passing through such screen.The top Mesh Opening must always be defined to allow 100% of the material passing through such screen.Mill Diameter, inside liners.Effective Grinding Lenght.Rotational Mill Speed, expressed as a percentage of the critical centrifugation speed of the mill.Total Apparent Volumetric Charge Filling - including balls and rocks, plus the interstitial voids in between such balls and rocks - expressed as a percentage of the net internal mill volume (inside liners).Apparent Volumetric Ball Filling Level, expressed as a percentage of the net internal mill volume (inside liners).Necessarily less or equal than the Total Charge Filling (Cell F14).This value represents the Volumetric Fractional Filling of the Voids - in between the balls and the rocks - by the retained slurry in the mill charge.In lack of actual measurements, a reasonable default value seems to be of the order of 50%.Represents the so-called Dynamic Angle of Repose (or Lift Angle) adopted during steady operation by the top surface of the mill charge ("the kidney") with respect to the horizontal. A reasonable default value for this angle is 40, but may be easily "tuned" to specific applications against any available actual power data.See spreadsheet Mill Power_SAG Mills.Component of the Total Mill Power Draw (Cell J14) contributed by the Ball Charge.Component of the Total Mill Power Draw (Cell J14) contributed by the Rocks.Component of the Total Mill Power Draw (Cell J14) contributed by the Interstitial Slurry.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.May be estimated from actual experimental data with the aid of SAGParam_Open (for industrial or pilot scale, continuous data).See About ... for further details.As suggested by Derek J. Barrat.In case the value in Cell I29 is not larger than this value, an increase in available open area should be then considered.Rate Constant kg in the expression :

Qg = kg A0 Vs

where Qg represents the flowrate of slurry through the grate openings, A0 the available open area and Vs the hold-up of slurry in the mill load.Expressed as a % of the effective cross sectional area of the mill.This Cell may be adjusted to any known, desired value by properly varying Cell G25.This Cell may be adjusted to any known, desired value by properly varying Cell G25.As suggested by Derek J. Barrat.In case the value in Cell I30 is not larger than this value, an increase in available open area should be then considered.Critical size above which ore particles are considered to be rocks; i. e. they do not fit in the interstitial voids and consequently, add to the total charge volume.A reasonable default value is close to 1/2".When the SAG mill operates in close circuit with a trommel or screen without pebble crushing the controlling opening dimension for modelling purposes is that of the trommel or screen, instead of the grate opening.

BM_Data_FileMoly-Cop Tools TM (Version 2.0)BALLSIM : Conventional Closed Circuit Grinding SimulatorCircuit TypeDUAL FEED(see Flowsheet)Simulation N0RemarksBase Case Example0Mill Dimensions and Operating Conditions3593BallsEff. DiameterEff. LengthSpeedChargeBallsApp. Dens.InterstitialLift0Overfillingftft% CriticalFilling,%Filling,%ton/m3Slurry, %Angle, ()575Slurry19.024.076.038.038.05.39100.030.04168Net kWrpm13.3610.0% Losses4631Gross kWCyclone Dimensions (inches) and Operating ConditionsNumberDiameterHeightInletVortexApex426.078.010.0010.005.00% Solids O'flow40.0% Solids U'flow74.3% Solids Mill Discharge72.0Main Simulated OutputsP80144.8Circulating Load2.224(Guess)Wio13.182.224(Actual)% Fines MD34.270.000(Delta)Q1710Ore Density, ton/m32.80Bpf0.322Balls Density, ton/m37.75Cycl. Psi10.0Feedrate, ton/hr (dry)500.0Sump Water515.0Sec. Feed, ton/hr (dry)0.0Feed Moisture, %27.2Sec. Feed Moisture, %0.0Feed Size DistributionSecondary FeediMeshOpeningMid-Sizeton/hr% Retained% Passington/hr% Passing12.1"50800100.00100.0021.48"38100439940.000.00100.000.00100.0031.05"26670318770.000.00100.000.00100.0040.742"18850224220.000.00100.000.00100.0050.525"13335158540.000.00100.000.00100.0060.371"94231121035.867.1792.830.00100.00736680793450.2910.0682.770.00100.00844699560352.1710.4372.330.00100.00963327395447.169.4362.900.00100.001082362280341.518.3054.600.00100.0011101651197536.157.2347.370.00100.0012141168138930.376.0741.300.00100.00132083398623.574.7136.580.00100.00142858970020.124.0232.560.00100.00153541749617.023.4029.160.00100.00164829535114.502.9026.260.00100.00176520824813.472.6923.560.00100.001810014717511.502.3021.260.00100.001915010412410.802.1619.100.00100.002020074889.601.9217.180.00100.0021-20003785.9217.180.000.000.00Make-up Ball Size, mm76.02.99inchesSelection Function Parameters :Expanded Form :alpha0alpha1alpha2dcritalpha02alpha120.0092520.65236405015.75>7.2701Suggested Default Values4.60>0.504.20