Tailings Dam

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Navigation: Main Page -> Models -> Material Handling Models

This model is only available in SysCAD 9.2 Build 133 and later.

General Description

The Tailings Dam model is used in the Dynamic mode to emulate a Tailings Dam, where most of the solids settle in the dam and the liquids form a layer that may be pumped out of the dam.

  • Currently the user may add reactions to the Liquid layer of this unit.
  • The user defines the percentage solids in both the settled solids layer and the liquids layer of the unit. The Tailings Dam will calculate the liquid split to the solid and liquid layer to satisfy the user defined solids percentages.


Diagram

TailingsDam2.png

The diagram shows the default drawing of the Tailings Dam, with all of the streams that have to be connected for the unit to operate.

The physical location of the streams connecting to the Tailings Dam is unimportant. The user may connect the streams to any position on the unit.

Inputs and Outputs

Label Required
Optional
Input
Output
Number of Connections Description
Min Max.
Feed Optional In 0 20 The slurry feed to the Tailings Dam.
CL_Feed Optional In 0 10 Liquid feed to the clarified liquor section of the Tailings Dam.
Overflow Required Out 1 1 Tailings Dam overflow stream from the Clarified Liquor layer.
CL_Out Optional Out 0 10 Outlet stream from the Clarified Liquor Tailings Dam overflow stream.
Bed Out Optional Out 0 1 Outlet stream from the Tailings Dam Solids layer.
Seepage Optional Out 0 1 Tailings Dam seepage from the Solids layer.
Vent Optional Out 0 1 Vent Stream (Vapour Only).

Model Theory

  • The Tailings Dam unit is a Dynamic unit that is used to store solids and liquids in separate layers.
  • The user may define reactions to occur in the liquid layer of the unit.
  • The user defines the operating parameters.

Flowchart

The following shows the sequence of events when evaluating the Tailings Dam model.

Tailings Dam Block Flow2.png

Data Sections

Summary of Data Sections

  1. TailingsDam tab - This first tab contains general information relating to the unit configuration.
  2. Results contains calculated information for flows into and out of the Tailings Dam and for both the clarified liquor and solids layers of the Tailings Dam.
  3. Content contains information for the material in the Tailings Dam - both the clarified liquor and solids layers.
  4. LL - Optional tab, only visible if Level lookup is enabled. Allows the user to create and populate the Level lookup table.
  5. PresetImg optional tab, only visible if the user has enabled UsePresetImg. It allows the user to define the composition and amount of material to use to 'pre set the Tailings Dam.
  6. CRB - Optional tab, only visible if the Reactions are enabled.
  7. Info tab - contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
  8. Links tab, contains a summary table for all the input and output streams.
  9. Audit tab - contains summary information required for Mass and Energy balance. See Model Examples for enthalpy calculation Examples.

Tailings Dam Page

Unit Type: TailingsDam - The first tab page in the access window will have this name.

Tag / Symbol Input / Calc Description/Calculated Variables / Options

Common Data on First Tab Page

Requirements

Reactions On / Off This allows the user to enable or disable Reactions in the Clarified Liquor layer. If Reactions are enabled then the tab CRB will be visible and the user can configure this page.
TargetBedSolids Input The required solids fraction in the settled solids in the Solids Layer.
FeedSolidsToCL Input The required solids fraction in the liquid split from the Feed stream to the Clarified Liquor layer.
MaxCLSolids Input The Maximum solids fraction in the Clarified Liquor layer. If the solids fraction exceeds this limit, perhaps due to reactions in the CRB, then the excess solids will be sent to the Solids layer.
VolumeSpecMethod Simple Total The user only has to specify the total Volume and Height of the Tailings Dam.
Lookup The user enters Lookup values that use the volume to determine surface area, height, etc. If this method is chosen then the LL tab page becomes visible and the user may enter values relating height and surface area to volume.
Volume Input / Calc The user enters the total volume of the Tailings Dam if Simple Total is used. Otherwise the calculated volume of material in the Tailings Dam is displayed if Lookup is used.
Height Input / Calc The user enters the total height of the Tailings Dam if Simple Total is used. Otherwise the calculated height of material in the Tailings Dam is displayed if Lookup is used.
OperatingP...
Method Atmospheric Outlet streams will be at Atmospheric Pressure. The atmospheric pressure is calculated by SysCAD based on the user defined elevation (default elevation is at sea level = 101.325 kPa). The elevation can be changed on the Species tab page of the Plant Model.
AutoDetect If there are any liquids AND no vapours present in the feed, outlet streams will take the highest pressure of the feeds. Else (eg. some vapours present) outlet streams will take the lowest pressure of the feeds.
LowestFeed Outlet streams will take the lowest pressure of the feeds.
HighestFeed Outlet streams will take the highest pressure of the feeds.
RequiredP Outlet streams will be at the user specified pressure.
IgnoreLowQm Tick Box This option is only visible if the AutoDetect, LowestFeed or HighestFeed methods are chosen. When calculating the outlet pressure and temperature of the tank, SysCAD will ignore the low flow feed streams should this option be selected. The low flow limit is set in the field below.
LowQmFrac Input This field is only visible if the IgnoreLowQm option is selected. This is the amount any stream contributes to the total flow. For example, if the total feed to the tank is 10 kg/s, and this field is set to 1%. Then any feed streams with less than 0.1 kg/s will be ignored in the pressure calculations.
Reqd Input This field is only visible if the RequiredP method is chosen. This is user specified pressure.
Result Display The actual pressure used for the sum of the feeds which will also be the outlet pressure (unless further model options change the pressure).
Evap...
Method None There is no evaporation from the unit.
MassFlow The user may specify the mass flow of water vapour from the unit.
VolumeFlow The user may specify the volume flow of water vapour from the unit.
MassFlowReqd / QmReqd Input Only visible if the evaporation method is MassFlow. The required mass flow of evaporated water from the unit.
VolFlowReqd / QvReqd Input Only visible if the evaporation method is VolumeFlow. The required volume flow of evaporated water from the unit.
Bed_Outlet... The material in the Bed Outlet stream will have the same composition as the solids layer in the Tailings Dam.
Method None There is no flow out from the solids layer (the 'bed').
MassFlow The user may specify the mass flow from the solids layer.
VolumeFlow The user may specify the volume flow from the solids layer.
RqdQm Input The required mass flow from the solids layer. Only visible if the Bed Outlet method is MassFlow.
RqdQv Input The required volume flow from the solids layer. Only visible if the Bed Outlet method is VolumeFlow.
Seepage_Outlet... The material in the Seepage Outlet stream will contain only Liquids with the same composition as the liquids in the solids layer in the Tailings Dam.
Method None There is no seepage flow from the solids layer.
MassFlow The user may specify the mass flow of the seepage from the solids layer.
VolumeFlow The user may specify the volume flow of the seepage from the solids layer.
RqdQm Input The required mass flow of the seepage from the solids layer. Only visible if the Seepage Outlet method is MassFlow.
RqdQv Input The required volume flow of the seepage from the solids layer. Only visible if the Seepage Outlet method is VolumeFlow.
CL_Outlet... The source of this stream is the clarified liquor layer in the Tailings Dam. If the user does not block a species then the material in the CL Outlet stream will contain material with the same composition as the Clarified Liquid layer in the Tailings Dam.
Method None There is no flow in the CL outlet stream.
MassFlow The user may specify the mass flow of the CL outlet stream.
VolumeFlow The user may specify the volume flow of the CL outlet stream.
RqdQm Input The required mass flow of the CL outlet stream. Only visible if the CL Outlet method is MassFlow.
RqdQv Input The required volume flow of the CL outlet stream. Only visible if the CL Outlet method is VolumeFlow.
CL.BlockedSpecies Species List The user may choose to block a species from flowing out of the CL outlet stream. If the user does not wish to block any species, then select '-'.
Options
UsePresetImg Tick Box If this is enabled then the user may use the pre-set image to initialise the Tailings Dam. The tab PresetImg will be available for the user to configure the compositions of both the solids and liquid layers of the Tailings Dam.
Empty_Bed Button Clicking on this button will empty the contents of the solids layer.
Empty_CL Button Clicking on this button will empty the contents of the liquid layer.
Empty_All Button Clicking on this button will empty the total contents of the unit - both the solids and liquid layers.
The following 3 buttons are only visible if UsePresetImg is enabled.
Preset_Bed Button Clicking on this button will copy the composition from the Pre-Set image for the Bed into the contents of the solids layer.
Preset_CL Button Clicking on this button will copy the composition from the Pre-Set image for the Clarified Liquor into the contents of the liquid layer.
Preset_All Button Clicking on this button will copy the composition from the Pre-Set image for both the Bed and Clarified Liquor into the contents of the solids and liquid layers.

Results Tab Page

Tag / Symbol Input/ Calc Description
Results
Dam.Mt Calc The total mass of material in the dam. This includes both the solid and liquid layers.
Dam.Vt Calc The total volume of material in the dam. This includes both the solid and liquid layers.
Dam.Lvl Calc The level in the Tailings Dam. This is calculated as a fraction of the total dam height.
Dam.Height Calc The height of material in the Tailings Dam.
Dam.SurfArea Calc The total surface area of the Tailings Dam. This is based on a cylindrical cylinder, unless the user has selected Lookup as the VolumeSpecMethod.
Dam.VolFrac Calc The fraction of the total volume in the Tailings Dam that contains material.
CLVolumeAvail Calc The available volume in the Tailings Dam, i.e. the difference in volume between the total Tailings Dam volume and the volume of material already in the dam.
Bed The following fields all refer to the solids layer.
BedT Calc The temperature in the solids layer.
BedMt Calc The mass of material in the solids layer.
Bed.Sf Calc The solids mass fraction in the solids layer.
Bed.Vol Calc The volume of material in the solids layer.
Bed.Rho Calc The material density in the solids layer.
Clarified Liquor The following fields all refer to the liquid layer.
Cl.T Calc The temperature of the liquid layer.
Cl.Mt Calc The mass of material in the liquid layer.
Cl.Sf Calc The solids mass fraction in the liquid layer.
Cl.Vol Calc The volume of material in the liquid layer.
Cl.Rho Calc The material density in the liquid layer.
Inlet Streams
FeedQm Calc The mass flow of material in all of the Feed streams.
CLFeedQm Calc The mass flow of material in all of the feed streams to the Liquid layer.
Outlet Streams Any streams that have method = None will NOT be displayed here.
CL.OutletQm Calc The mass flow of material in the liquid outlet streams.
OFQm Calc The mass flow of material in the overflow stream.
Bed.OutletQm Calc The mass flow of material in the solids outlet stream.
Seepage.Qm Calc The mass flow of material in the seepage outlet stream.
VentQm Calc The mass flow of material in the vent stream.
Internal Streams
NettQm Calc The net mass flow of material between the solid and liquid layers.
EvapQm Calc The mass flow of evaporated material.
FeedtoBed.Qm Calc The mass flow of material from the Feed streams to the solids layer.
FeedtoBed.Sf Calc The solids mass fraction in the material from the Feed streams to the solids layer.
FeedtoCL.Qm Calc The mass flow of material from the Feed streams to the liquid layer.
FeedtoCL.Sf Calc The solids mass fraction in the material from the Feed streams to the liquid layer.
CLtoBedQm Calc The mass flow of material from the liquid layer to the solid layer This occurs if the solids fraction in the liquid layer exceeds the maximum solid fraction specified in the liquid layer.
Extra Internal Stuff
SolFracToUF Calc The solid fraction in the internal stream from the liquid to the solid layer.
LiqFracToUF Calc The liquid fraction in the internal stream from the liquid to the solid layer.


Content Tab Page

This tab page contains 2 tables, as described below.


Table 1 - Species Masses

Each species in the project will be shown on a separate row in the table. The values for each species are explained below:

Column Heading Description
Species This column will contain a list of all the species in the project.
Bed The mass of the species in the solids layer.
CL The mass of the species in the liquid layer.
Total The total mass of the species in the Tailings Dam. This will be the sum of the species in the solid and liquid layers.
MF.Bed The Mass Fraction of the species in the solids layer.
MF.CL The Mass Fraction of the species in the liquid layer.


Table 2 - Overall Content Values

Variable Bed CL Total
TotalMass / Mt The mass of material in the solids layer. The mass of material in the liquid layer The total mass of material in the Tailings Dam.
TotalVolume / Vt The volume of material in the solids layer. The volume of material in the liquid layer The total volume of material in the Tailings Dam.
SolidFrac / Sf The solid mass fraction in the solids layer. The solid mass fraction in the liquid layer The solid mass fraction of the Total amount of material in the Tailings Dam.
LiquidFrac / Lf The liquid mass fraction in the solids layer. The liquid mass fraction in the liquid layer The liquid mass fraction of the Total amount of material in the Tailings Dam.
Temperature / T The temperature of the solids layer. The temperature of the liquid layer
Density / Rho The density of the solids layer. The density of the liquid layer

Pre-Set Image Tab Page

This tab page is used to define the state of the unit when the user activates the 'Preset' action. This is done by either by clicking on the 'Preset' button, or using the 'Preset' option on start. The page normally contains 2 tables to define the preset image, as described below.


Table 1

Define Pre-set image method and parameters. The fields are explained below:

Tag/Symbol Input Description
Method Empty The preset action will empty the Tailings Dam, i.e. this will have the same effect as clicking on the 'Empty' button. No other fields will be displayed on this page if this option is selected.
Mass The user sets the mass of each species in the unit. These values will then be used when the unit is preset.
Level The user sets required levels in the solid and liquid layers in the unit. The user may also set the required composition of the species in the unit (the default is 100% water). The values will then be used when the unit is preset.
Height The user sets required heights in the solid and liquid layers in the unit. The user may also set the required composition of the species in the unit (the default is 100% water). The values will then be used when the unit is preset.
Temperature Input The required temperature of the unit when Preset.
The following 2 fields are visible if the Method = Level.
Bed.Level Input The level of the solid layer as a fraction of the Total unit height.
CL.Level Input The level of the liquid layer as a fraction of the Total unit height. This MUST be greater or equal to the solid level.
The following 2 fields are visible if the Method = Height.
Bed.Height Input The height of the solid layer.
CL.Height Input The height of the liquid layer. This MUST be greater or equal to the solid height.


Table 2 - Species Composition

  • Method = Mass
    The user may set the individual masses of each species.
  • Method = Level or Height
    The user may set the individual composition of each species.

Note: If the user does not set any individual species masses or compositions, then the default is 100% water.

Adding this Model to a Project

Insert into Configuration file

Sort either by DLL or Group.

 

DLL:

MatHand2.dll

Units/Links

Material Handling: Tailings Dam

OR

Group:

Mass Transfer

Units/Links

Material Handling: Tailings Dam

See Project Configuration for more information on adding models to the configuration file.

Insert into Project

 

Insert Unit

Material Handling

Tailings Dam

See Insert Unit for general information on inserting units.

Hints and Comments

  1. If the user has the geometry of the unit, then use the 'Level Lookup' functionality to relate the height and surface area to the volume of the material.