AU2018271139B2 - A train loading system - Google Patents
A train loading system Download PDFInfo
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- AU2018271139B2 AU2018271139B2 AU2018271139A AU2018271139A AU2018271139B2 AU 2018271139 B2 AU2018271139 B2 AU 2018271139B2 AU 2018271139 A AU2018271139 A AU 2018271139A AU 2018271139 A AU2018271139 A AU 2018271139A AU 2018271139 B2 AU2018271139 B2 AU 2018271139B2
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
- B65G67/00—Loading or unloading vehicles
- B65G67/02—Loading or unloading land vehicles
- B65G67/04—Loading land vehicles
- B65G67/22—Loading moving vehicles
Abstract
A train loading system is disclosed for loading material onto cars of a train. The system comprises a reclaimer arranged to reclaim material for loading onto a train from a material bench at a reclaim rate, and a surge bin arranged to receive material from the reclaimer and supply material to cars of a train that travels under the surge bin. The surge bin includes a clam having a trim position controllable to modify an outflow rate of material from the surge bin and thereby a train loading rate of material onto a train, the clam trim position dependent on the train speed such that an increase in the train speed causes an increase in the clam trim position and thereby an increase in the train loading rate, and a decrease in the train speed causes a decrease in the clam trim position and thereby a decrease in the train loading rate. The system also includes a feed forward component arranged to determine a feed forward train speed based on the reclaim rate, the feed forward train speed being used to set the train speed, and a feedback component arranged to modify the feed forward train speed based on the amount of material in the surge bin. The amount of material in the surge bin is maintained at a level such that stopping of the reclaimer or stopping of the train because of the level of material in the surge bin is avoided.
Description
A TRAIN LOADING SYSTEM
Field of the Invention The present invention relates to a train loading system for loading mined material onto a train at a mine operation.
Background of the Invention It is known to provide a mine operation such as a mine site with a train loading facility arranged to facilitate loading of material onto dedicated material transport trains by train loadout operators.
Typically, ore is carried by a conveyor from a reclaimer to a surge bin, and ore flows out of the surge bin and into cars of the train as the train continuously moves under the bin. The rate of ore flow from the surge bin is controlled by opening and closing a clamshell.
For cost reasons, it is highly undesirable to stop a reclaimer before completion of a bench or to stop a train during loading. In order to ensure that train loading is not interrupted, it is desirable to maintain the surge bin level close to a defined level, since an empty bin will require the train to be stopped, and a full bin will require the reclaimer to be stopped. However, the rate or ore flow from the reclaimer is highly variable, and therefore the surge bin fill rate and bin level is also variable.
As each car passes under the surge bin, the clam must open and close at the correct times according to the position of the car relative to the clam, and with the clam at the correct opening position ("trim"). The trim setting of the clam determines the rate of ore flow though the clam while it is open, and therefore the trim setting must be set according to the train speed. In order to regulate the bin level, an operator adjusts the ore flow rate from the surge bin by manually adjusting the train speed and the clam trim remotely in real time.
However, such an arrangement for managing train loading is cumbersome, inefficient and prone to error.
Summary of the Invention
It will be understood that in the present specification a mine operation means any operation or facility associated with extracting, handling, processing and/or transporting bulk commodities in a resource extraction environment or part of such a process, for example mine sites, rail facilities, port facilities, and associated infrastructure.
In accordance with a first aspect of the present invention, there is provided a train loading system for loading material onto cars of a train, the system comprising:
a reclaimer arranged to reclaim material for loading onto a train from a material bench at a reclaim rate;
a surge bin arranged to receive material from the reclaimer and supply material to cars of a train that travels under the surge bin, the surge bin including a clam having a trim position controllable to modify an outflow rate of material from the surge bin and thereby a train loading rate of material onto a train, the clam trim position dependent on the train speed such that an increase in the train speed causes an increase in the clam trim position and thereby an increase in the train loading rate, and a decrease in the train speed causes a decrease in the clam trim position and thereby a decrease in the train loading rate;
a feed forward component arranged to determine a feed forward train speed based on the reclaim rate, the feed forward train speed being used to set the train speed; and
a feedback component arranged to modify the feed forward train speed based on the amount of material in the surge bin;
whereby the amount of material in the surge bin is maintained at a level such that stopping of the reclaimer or stopping of the train because of the level of material in the surge bin is avoided. In an embodiment, the feed forward component is arranged to determine a feed forward train speed according to the following relationship between the reclaim rate and the train speed:
Reclaim rate = P * Speed
where Speed is the train speed, Reclaim rate is the reclaim rate of the reclaimer, and P is a proportionality constant.
In an embodiment, the feed forward component comprises at least one filter arranged to filter the reclaim rate, for example using at least one low pass filter.
In an embodiment, the feed forward component comprises an initialisation component arranged to initialise the feed forward component to ensure bumpless transfer as the train loading system is switched from manual mode to automatic mode. The initialisation component may be arranged to initialise the feed forward component with an initialisation reclaim rate value determined based on a previous train speed value.
In an embodiment, the system comprises a weightometer arranged to measure the reclaim rate from the reclaimer.
In an embodiment, the feedback component is arranged to modify the feed forward train speed based on a difference between the amount of material in the surge bin and an aim bin level indicative of a defined amount of material in the surge bin, wherein a positive difference between the amount of material in the surge bin and the aim bin level causes the feedback component to positively modify the feed forward train speed and thereby increase the train loading rate and reduce the amount of material in the surge bin, and a negative difference between the amount of material in the surge bin and the aim bin level causes the feedback component to negatively modify the feed forward train speed and thereby reduce the loading rate and increase the amount of material in the surge bin.
The system may include a bin level sensor arranged to provide information indicative of the amount of material in the surge bin. In an embodiment, the feedback component is arranged to produce a bin level error value indicative of the difference between the amount of material in the surge bin and the aim bin level, and the feedback component comprises a discrete proportional integral controller arranged to produce a train speed error based on the bin level error value, the train speed error applied to the feed forward train speed to modify the feed forward train speed.
In an embodiment, the discrete proportional integral controller is arranged to operate in accordance with the following equation: CntrllrOut = Sat(CntrllrOuti-i) + Kp(error - errori-i) + Ki (t - ti-i) error (4) where
CntrllrOuti-1 is the controller output last calculated by the feedback controller 54, the controller output corresponding to the feedback train speed error value that is combined with the feed forward value determined by the feed forward controller 52; error is a bin level error calculated by subtracting the aim bin level 80 from the measured bin level 82; error,.-! is the previous bin level error last calculated by the feedback controller 54; t is time [s]; hi is the time since the last calculation by the feedback controller 54;
Kp is a proportional term = 0.0032 [km/(tonnes.hr)]; and Ki is an integral term = 1 .5873 E-05 [(s.km)/tonnes.hr].
In an embodiment, the system is arranged to apply saturation such that the amount of modification to the train speed is limited.
In an embodiment, the system is arranged to apply a feedback multiplier such that the amount of modification to the train speed is limited. The feedback multiplier may be approximately 15%.
In an embodiment, the feed forward train speed used to set the train speed is applied to a train once per train car, for example at each transition between adjacent cars under the surge bin.
In an embodiment, the system is arranged to increase the amount of material in the surge bin prior to a transition of the reclaimer between material benches. In an embodiment, the system is arranged to increase the amount of material in the surge bin prior to a transition of the reclaimer between material benches by reducing the speed of the train and thereby reducing the loading rate from the surge bin.
In an embodiment, the system is arranged to increase the amount of material in the surge bin prior to a transition of the reclaimer between material benches by increasing the aim bin level, thereby negatively increasing the difference between the amount of material in the surge bin and the aim bin level, reducing the speed of the train and reducing the loading rate from the surge bin. In an embodiment, the system is arranged to increase the amount of material in the surge bin prior to a transition of the reclaimer between material benches at a time based on the amount of material remaining in a material bench.
In an embodiment, the system is arranged to increase the aim bin level based on material bench type.
In an embodiment, the system is arranged to determine the clam trim position according to the following equations: Base Trim = Current Trim - F '(Current Speed) where F(Current Speed) is a function of the train speed using the current train speed for given by: F(x) = / ix2 + k2x wherein fci and k2 are constants based on analysis of actual loadout data; and
New Trim = Base Trim + F(New Speed) where F(New Speed) is the function F(x) using a new train speed for x calculated by the train speed controller.
5
In an embodiment, the system is arranged such that an increase in train speed is delayed by one car.
In an embodiment, the system is arranged such that a decrease in train speed is0 applied to a car immediately.
In accordance with a second aspect of the present invention, there is provided a method of loading material onto cars of a train at a mine operation, the method comprising:
5 reclaiming material for loading onto a train from a material bench at a reclaim rate;
receiving material from the reclaimer in a surge bin, and supplying material from the surge bin to cars of a train that travels under the surge bin, the surge bin including a clam having a trim position controllable to modify an outflow rate of material from the o surge bin and thereby a train loading rate of material onto a train, the clam trim position dependent on the train speed such that an increase in the train speed causes an increase in the clam trim position and thereby an increase in the train loading rate, and a decrease in the train speed causes an decrease in the clam trim position and thereby a decrease in the train loading rate;
5 determining a feed forward train speed based on the reclaim rate, the feed forward train speed being used to set the train speed; and
modifying the feed forward train speed based on the amount of material in the surge bin;
whereby the amount of material in the surge bin is maintained at a level such o that stopping of the reclaimer or stopping of the train because of the level of material in the surge bin is avoided.
Brief Description of the Drawings 5 The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a diagrammatic perspective representation of a train loading system according to an embodiment of the present invention;
Figure 2 is a block diagram of control components of the train loading system shown in Figure 1 ;
Figure 3 is a schematic diagram illustrating functional components of a train speed controller of the train loading system shown in Figures 1 and 2;
Figure 4 shows a plot illustrating the relationship between train speed and train loading rate, and a plot illustrating the relationship between train speed and train loading time in the train loading system shown in Figures 1 to 3;
Figure 5 shows a plot illustrating a measured reclaim rate and a filtered reclaim rate; and
Figure 6 shows plots illustrating the relationship between a surge bin aim level and a measured surge bin level, a plot illustrating an error between the surge bin aim level and the measured surge bin level, and plots illustrating a saturated controller output and a feedback response signal.
Description of an Embodiment of the Invention
An embodiment of a train loading system will now be described with reference to mine operations in the form of mine sites, although it will be understood that other mine operations wherein train loading operations occur are envisaged.
An example train loading system 10 is shown diagrammatically in Figure 1 . The train loading system 10 includes a reclaimer 12 that reclaims material, in this example ore, from a material bench, and a conveyor 14 arranged to convey the reclaimed ore to a surge bin 16. The rate of ore flow from the reclaimer 12 is measured, in this example by a weightometer 18 typically disposed 100 - 500m from the surge bin 16. During train loading, ore flows out of the surge bin 16 and into cars 22 of a train 20 as the train continuously moves under the surge bin 16 in the direction of arrow 24. The rate of ore flow from the surge bin 16 is controlled by opening and closing a clamshell (not shown).
It is desirable to maintain the amount of ore in the surge bin 16 at a defined partially full level since an empty bin would require the train to be stopped, and a bin that has been
filled too high would require the reclaimer 12 to be stopped. Both of these
circumstances are highly undesirable for cost reasons.
Figure 2 illustrates control components 30 of the train loading system 10. Using the control components 30, it is possible to maintain the bin level at a sufficient partially full level that an empty bin or full bin situation is avoided, and therefore a reclaimer or train stopping event is avoided.
The control components 30 include a reclaimer flow rate measuring device, in this example the weightometer 18, arranged to measure the rate of ore flow from the reclaimer 12; a bin level sensor 34 arranged to measure the level of ore in the surge bin 16; an aim bin value 35 that defines the desired surge bin level 16; and a train speed controller 36 that determines an adjusted train speed 38 and an adjusted clam trim position 40 based on the measured reclaimer flow rate, the aim bin level 35 and the measured surge bin level.
The rate of ore loaded into cars 22 of a train 20 is fundamentally limited by the reclaimer flow rate, since the reclaimer flow rate determines the rate that the surge bin 16 is filled, and therefore the required ore outflow rate from the surge bin 16 in order for the surge bin 16 to maintain a desired fill level. If a train is loaded at a consistently higher rate than the reclaim rate, the bin will empty. If a train is loaded at a consistently lower rate than the reclaim rate, the bin will fill. The train loading rate is defined by the ore outflow rate, and the ore outflow rate can be controlled by adjusting the speed of the train 20, since the train speed directly determines the clam position required in order to appropriately fill the cars 22 of the train 20.
As shown in graph 58 in Figure 4, a loading rate plot 60 indicates that the loading rate of a car 22 of a train 20 is directly proportional to the train speed, and a loading time plot 62 indicates that loading time of the car 22 is also directly proportional to the train speed.
While the loading rate is actually defined by the clam position of the surge bin 16, the loading rate of a car 22 can be considered to be directly proportional to the train speed because a faster train speed necessitates a faster flow rate and therefore a more open clam position in order to fill a train car.
The following equation represents the relationship between loading rate (ore outflow rate from the surge bin) and train speed. Rate Out = P * Speed (1 ) where Speed is the train speed, Rate Out is the required loading rate of a car in order to achieve a full car when the train is travelling at the Speed, and P is a proportionality constant.
The proportionality constant P can be calculated as follows.
If it is assumed that a car 22 of a train 20 holds 120 tonnes when full and the length of the car 22 is 10m, then in order to fill the car 22, 12 tonnes/m must be loaded into the car 22. If the speed of the car 22 is 0.8 km/hr (0.222 m/s), the required loading rate is given by 12 tonnes/m x 0.222 m/s = 2.667 tonnes/s. This gives a proportionality constant P of 2.667/0.8 = 3.3 tonnes. hr/s. km.
Using this relationship, the train speed controller 36 is able to set a 'feed forward' train speed that is appropriate for the current reclaimer flow rate, since it can be assumed that the reclaimer flow rate is also directly proportional to the train speed if the bin level remains constant.
Reclaim rate = P * Speed (2)
During testing, the output rate from the surge bin 16 was determined using known train speeds for seven different trains. The surge bin level was approximated using the difference between the bin output rate and the input reclaim rate during loading of the trains. Agreement with the measured bin level was found to be most accurate with a proportionality constant P of 3.25, instead of the proportionality constant P of 3.3 determined using the above equation (1).
The train speed controller 36 is arranged to produce a feed forward train speed value based on the relationship between reclaimer flow rate and train speed defined in equation (2) above.
A determination of the train speed required for a measured reclaim rate involves a balance between minimising speed disturbances and maintaining a stable bin level. If the flow rate into the surge bin 16 is not exactly equal to the flow rate out of the surge bin 16, small errors in the controller determined train speed can accumulate over time and lead to an undesirable bin level. Therefore, in order to maintain the bin level at a desirable level, direct feedback to the determined train speed is provided by determining a train speed error to apply to the feed forward determined train speed. The train speed error is calculated by determining an error between a measured bin level and the aim bin level 35.
Automation of train speed is therefore achieved using 2 components of the train speed controller 36: a feed forward control component, which determines a feed forward train speed using the train speed/reclaim rate relationship defined by the above equation (2); and a feedback control component that adjusts the determined feed forward train speed using a train speed error calculated using an error determined between the measured bin level and the aim bin level 35. Referring to Figure 3, functional components 50 of the train speed controller 36 are shown in more detail.
The train speed controller components 50 include a feed forward controller 52 and a feedback controller 54 that together produce a train speed output 56 used to set the train speed. The feed forward controller 52 and the feedback controller 54 are arranged to calculate a respective feed forward train speed value and a train speed error value for each train car 22.
The feed forward controller 52 receives a measured reclaim rate 64 from the weightometer 18. However, since the measured reclaim rate value is highly variable, the measured reclaim rate is filtered using at least one low pass filter 66. In this example, two 240s cascaded low pass filters having a gain of 1 are used that are defined by the following equation.
where
The filtered reclaim rate value is used by a train speed calculator 68 to calculate a feed forward train speed value based on equation (2) above.
Figure 5 shows example reclaim rate plots 130 that include a measured reclaim rate plot 132 and a filtered reclaim rate plot 134. The filtered reclaim rate provides a time averaged value for the measured reclaim rate so that the high variability in the measured reclaim rate is not passed on to the feed forward train speed value used to set the train speed.
The feed forward controller 52 also includes initialisation components that include a delay component 70 and an initialisation reclaim rate calculator 72. The purpose of the initialisation components is to initialise the feed forward controller 52 and ensure bumpless transfer as the train loading system 10 is switched from manual to automatic mode. When the system is switched into automatic mode, the low pass filters 66 are initialised with an initialisation reclaim rate value that has been calculated using equation (2) based on a previous most recent measured train speed value. This is represented by the delay component 70. For example, in the example represented by the plots in Figure 5, the system 10 is in manual mode at 400 seconds and is placed in automatic mode at 401 seconds. Prior to switching to automatic mode, at 400 seconds, the measured train speed was 0.75 km/hr. Based on this value for the train speed, an initialisation reclaim rate value is calculated using equation (2) as 0.75 x 3.25 = 2.4375 tonnes/s.
The feedback controller 54 receives a value for the aim bin level 35 representing a desirable bin level to avoid an empty bin or an overfilled bin situation, and a measured value for the current bin level 82. The aim bin level 35 and the measured value for the
current bin level 82 are compared by a bin level error calculator 84 in order to obtain a bin level error value. The bin level error value is used by a discrete proportional integral controller to modify the feed forward train speed and thereby also change the bin level to a value closer to the aim bin level (because the train loading rate will also change as the train speed changes).
The discrete proportional integral controller of the feedback controller 54 operates in accordance with the following equation. CntrllrOut = Sat(CntrllrOuti-i) + Kp(error - errors) + Ki (t - tj-i) error (4) where
CntrllrOuti-1 is the controller output last calculated by the feedback controller 54, the controller output corresponding to the feedback train speed error value that is combined with the feed forward value determined by the feed forward controller 52; error is a bin level error calculated by subtracting the aim bin level 80 from the measured bin level 82; erron-i is the previous bin level error last calculated by the feedback controller 54; t is time [s]; hi is the time since the last calculation by the feedback controller 54; Kp is a proportional term = 0.0032 [km/(tonnes.hr)]; and Ki is an integral term = 1 .5873 E-05 [(s.km)/tonnes.hr].
As shown in Figure 3, the feedback controller 54 includes an adder 86 that adds together the output of a time dependent error component 88 corresponding to the term Ki (t - ti-i) error of equation (4) above, the output of an error difference component 90 corresponding to the term Kp(error - errors) of equation (4) above, and the
saturated controller output last calculated by the feedback controller 54 corresponding to the term Sat(CntrllrOu --\) of equation (4) above.
The error difference component 90 includes an error delay component 94, an error change calculator 96 that differences the current bin level error and a bin level error previously calculated by the error calculator 84, and a proportional term constant Kp 98 that is applied to the calculated bin level error difference value calculated by the error change calculator 96. The output of the adder 86 is saturated by a feedback saturation component 100 in order to avoid integral windup, the feedback saturation component 100 defining a minimum saturated feedback value of -0.85 km/hr and a maximum saturated feedback value of 0.85 km/hr. The feedback controller 54 controls how much influence the saturated feedback value has on the train speed output 56 by applying a feedback constant 102 to the saturated feedback value. In this example, the feedback constant 102 is set at 15%, and consequently the maximum speed change is: +/-0.85 x 0.15 = +/-0.13km/hr. The train speed error value produced by the feed forward controller 52 is added to the feed forward train speed value produced by the train speed calculator 68 at adder 104 so as to provide a degree of error correction to the feed forward train speed value, and the result is saturated by a speed saturation component 106, the speed saturation component 106 defining a minimum saturated speed value of 0.45 km/hr and a maximum saturated speed value of 0.85 km/hr.
Hysteresis of 0.05 and quantisation of 0.025 are then applied to the speed saturated value produced by the speed saturation component 106 by a quantisation component 108.
After hysteresis and quantisation, the output of the train speed output 56 produced is used to set the train speed.
In the present embodiment, the train speed controller 36 is implemented using a programmable logic controller (PLC), although it will be understood that other implementations are envisaged. Speed changes are calculated continuously, but in the present embodiment are only applied to the train once per car, in the present embodiment at the transitions between cars 22 under the surge bin 16.
Using the above methodology, the train speed is continuously controlled during reclamation of material in a bench based on the current reclaim rate and the error between the current measured bin level and the aim bin level.
It will be understood however that some interruptions to the reclaim rate during loading are unavoidable, for example as the reclaimer moves between a completed bench of material and a new bench of material.
Bench changes stop the reclaimer 12 for 3-15 minutes, and stopping the train to match this is highly undesirable for efficiency and cost reasons. In order to avoid a situation wherein the surge bin 16 reaches empty before a car 22 is full because of a transition between benches, which would necessitate stopping the train 20, it is desirable to reduce the speed of the train 20 and modify the clam position according to the train speed so that the train fills more slowly and the bin level reduces more slowly. By intervening and increasing the aim bin level, the speed of the train will automatically be reduced by the feedback controller 54 of the train control system 10 so that the ore outflow rate decreases. Therefore, in order to prepare the surge bin 16 for an upcoming bench change that will cause a reduction in the surge bin fill rate, the aim bin level can be raised prior to transitioning benches in order to cause the amount of material in the surge bin 16 to increase to compensate for a future bench change wherein less material is delivered to the surge bin 16 by the reclaimer 12 and conveyor
14.
Referring to Figure 6, plots 140 representing operation of the feedback controller 54 are shown. The plots 140 include an aim bin level plot 142 representing the aim bin level set by the train speed controller 36; a measured bin level plot 144 representing
the actual level of material in the surge bin 16; a bin level error plot 146 representing the bin level error output by the error calculator 84 of the feedback controller 54, that is, the difference between the actual bin level and the aim bin level; a saturated controller output plot 148 representing the saturated output produced the feedback saturation component 100 of the feedback controller; and a train speed error plot 150
representing the train speed error value produced by the feedback controller 54 and used by the train speed controller 36 to adjust the train speed.
As shown in the aim bin level plot 142, the aim bin level is increased prior to a bench change, which causes the bin level error to immediately increase in magnitude
(negatively), as shown in the bin level error plot 146. A negative increase in the bin level error causes the system to assume that the surge bin is emptying, which causes the train speed value at the train speed output 56 to reduce, the loading rate to reduce, and the material level in the surge bin 16 to increase, as shown at section 152 of the measured bin level plot 144. When the bench change occurs and the impact of a consequent reduced reclaim rate reaches the surge bin 16, the level of material in the surge bin will reduce, as shown at section 154 of the measured bin level plot 144. After the bench transition has occurred and the impact of a consequent increased reclaim rate reaches the surge bin 16, even though the aim bin level has been reduced, the level of material in the surge bin will still increase, as shown at section
156 of the measured bin level plot 144, because the difference between the current bin level and the aim bin level is still negative. As shown in the measured bin level plot 144 at section 158, during reclamation of a bench the bin level is maintained close to the aim bin level by the train speed controller 36.
As shown in the saturated controller output plot 148 and the train speed error value plot 150, the train speed error value moves between a maximum train speed increase value of about 0.13km/hr and a maximum train speed decrease value of about 0.13km/hr, depending on whether the current bin level is respectively above or below the aim bin level.
Speed changes are calculated continuously, but applied once per car. Therefore, increasing the aim bin level to a level above the current bin level causes a train speed decrease up to a maximum decrease of 0.13km/hr per car, which causes the level of material in the surge bin to increase in preparation for a bench change, thereby
reducing the likelihood that the surge bin will empty during the bench change which would necessitate stopping of the train 20.
The timing of raising of the aim bin level is determined by monitoring the amount of material in the current bench according to the following equation.
Time remaining = BenchRemainTonnes I (3.25 * TrainSpeed) (6)
Where Time remaining is an estimate of the time remaining until the current bench has been fully reclaimed, BenchRemainTonnes is the amount in tonnes of material remaining in the current bench and TrainSpeed is the current train speed.
When the time remaining falls below a defined trigger time value, the train speed controller 36 causes the aim bin level to increase.
The trigger time value and the value of the raised aim bin level may be set according to the bench type, for example so that for some benches the aim bin level is increased earlier than others and to a different raised aim bin level. For example, Table 1 below shows example trigger times and aim bin levels for different bench transitions.
Table 1 The timing of lowering of the aim bin level is determined by appropriate site personnel, and approximately coincides with recommencement of ore flowing into the surge bin after a bench change.
At the end of a train, if the amount of material currently in the surge bin 16 is sufficient to complete loading, the train speed should be set to a constant reference speed and all control disabled. As a consequence, train loading will complete at a constant rate,
unless the operator enters a new reference speed. Without control disabled, the train would slow down to the minimum speed unnecessarily as the surge bin empties.
Optimal control of the trim of a train loadout clam is complex. However, it is understood that as the train speed varies, the trim requirement also varies such that as the train speed increases the trim should also increase (that is, the clam increasingly opens) to allow the flow rate to increase in response to the reduced time available to load a train car 22.
The train loading system 10 uses a simple relationship between train speed and trim to determine the trim setting, without attempting to provide automatic control for variations such as product type, material flow properties or density.
When automatic trim control is enabled, the system calculates a "base trim" which corresponds to an initial trim setting.
Trim = Current Trim - F(Current Speed) (7) where F(Current Speed) is a function of the train speed using the current train speed for , as follows.
/ l 2 + ¾ (8) and wherein fci and k2 are constants based on analysis of actual loadout data.
The train loading system 10 then calculates a new trim value for each change in train speed calculated by the train speed controller 36 according to the following equation.
New Trim = Base Trim + F(New Speed) (9)
Where F(New Speed) is the function (8) above using a new train speed for calculated by the train speed controller 36.
It will however be understood that an operator may make occasional adjustments to the base trim, for example due to changes in product type, material flow properties or density. Trim changes are synchronised with train speed changes and applied at a transition between cars 22 of a train 20.
The response of the speed of a train car 22 to an increase in speed of the train 20 varies depending on the position of the car 22 in the train consist. In general, however, it can be assumed that the car 22 will reach the speed of the train within the time it takes to load one car 22. For this reason, trim changes in response to train speed increases are delayed by one car.
The response of the speed of a train car 22 to a decrease in speed of the train 20 is faster and more consistent since the cars have brakes that are used to slow them down. Therefore, trim changes in response to a train speed decrease are applied immediately.
The above function F(x) in equation (8) is implemented in the present embodiment as a lookup table with a function generator in PLC code, although it will be understood that other variations are envisaged.
It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.
In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.
Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.
Claims (46)
1 . A train loading system for loading material onto cars of a train, the system comprising:
5 a reclaimer arranged to reclaim material for loading onto a train from a material bench at a reclaim rate;
a surge bin arranged to receive material from the reclaimer and supply material to cars of a train that travels under the surge bin, the surge bin including a clam having a trim position controllable to modify an outflow rate of material from the surge bin and0 thereby a train loading rate of material onto a train, the clam trim position dependent on the train speed such that an increase in the train speed causes an increase in the clam trim position and thereby an increase in the train loading rate, and a decrease in the train speed causes a decrease in the clam trim position and thereby a decrease in the train loading rate;
5 a feed forward component arranged to determine a feed forward train speed based on the reclaim rate, the feed forward train speed being used to set the train speed; and
a feedback component arranged to modify the feed forward train speed based on the amount of material in the surge bin;
o whereby the amount of material in the surge bin is maintained at a level such that stopping of the reclaimer or stopping of the train because of the level of material in the surge bin is avoided.
2. A train loading system as claimed in claim 1 , wherein the feed forward
5 component is arranged to determine a feed forward train speed according to the
following relationship between the reclaim rate and the train speed:
Reclaim rate = P * Speed 0 where Speed is the train speed, Reclaim rate is the reclaim rate of the reclaimer, and P is a proportionality constant.
3. A train loading system as claimed in claim 1 or claim 2, wherein the feed forward component comprises at least one filter arranged to filter the reclaim rate.5
4. A train loading system as claimed in claim 3, wherein the at least one filter comprises at least one low pass filter.
5. A train loading system as claimed in any one of the preceding claims, wherein the feed forward component comprises an initialisation component arranged to initialise the feed forward component to ensure bumpless transfer as the train loading system is switched from manual mode to automatic mode.
6. A train loading system as claimed in claim 5, wherein the initialisation component is arranged to initialise the feed forward component with an initialisation reclaim rate value determined based on a previous train speed value.
7. A train loading system as claimed in any one of the preceding claims, wherein the system comprises a weightometer arranged to measure the reclaim rate from the reclaimer.
8. A train loading system as claimed in any one of the preceding claims, wherein the feedback component is arranged to modify the feed forward train speed based on a difference between the amount of material in the surge bin and an aim bin level indicative of a defined amount of material in the surge bin, wherein a positive difference between the amount of material in the surge bin and the aim bin level causes the feedback component to positively modify the feed forward train speed and thereby increase the train loading rate and reduce the amount of material in the surge bin, and a negative difference between the amount of material in the surge bin and the aim bin level causes the feedback component to negatively modify the feed forward train speed and thereby reduce the loading rate and increase the amount of material in the surge bin.
9. A train loading system as claimed in any one of the preceding claims, wherein the system includes a bin level sensor arranged to provide information indicative of the amount of material in the surge bin.
10. A train loading system as claimed in any one of the preceding claims, wherein the feedback component is arranged to produce a bin level error value indicative of the difference between the amount of material in the surge bin and the aim bin level, and
the feedback component comprises a discrete proportional integral controller arranged to produce a train speed error based on the bin level error value, the train speed error applied to the feed forward train speed to modify the feed forward train speed.
1 1 . A train loading system as claimed in any one of the preceding claims, wherein the system is arranged to apply saturation such that the amount of modification to the train speed is limited.
12. A train loading system as claimed in any one of the preceding claims, wherein the system is arranged to apply a feedback multiplier such that the amount of modification to the train speed is limited.
13. A train loading system as claimed in claim 12, wherein the feedback multiplier is approximately 15%.
14. A train loading system as claimed in any one of the preceding claims, wherein the feed forward train speed used to set the train speed is applied to a train once per train car.
15. A train loading system as claimed in claim 14, wherein the feed forward train speed used to set the train speed is applied to a train at each transition between adjacent cars under the surge bin.
16. A train loading system as claimed in any one of the preceding claims, wherein the system is arranged to increase the amount of material in the surge bin prior to a transition of the reclaimer between material benches.
17. A train loading system as claimed in claim 16, wherein the system is arranged to increase the amount of material in the surge bin prior to a transition of the reclaimer between material benches by reducing the speed of the train and thereby reducing the loading rate from the surge bin.
18. A train loading system as claimed in claim 16, wherein the system is arranged to increase the amount of material in the surge bin prior to a transition of the reclaimer between material benches by increasing the aim bin level, thereby negatively
increasing the difference between the amount of material in the surge bin and the aim bin level, reducing the speed of the train and reducing the loading rate from the surge bin.
19. A train loading system as claimed in claim 16, wherein the system is arranged to increase the amount of material in the surge bin prior to a transition of the reclaimer between material benches at a time based on the amount of material remaining in a material bench.
20. A train loading system as claimed in any one of the preceding claims, wherein the system is arranged to increase the aim bin level based on material bench type.
21 . A train loading system as claimed in any one of the preceding claims, wherein the system is arranged to determine the clam trim position according to the following equations:
Base Trim = Current Trim - F(Current Speed) where F(Current Speed) is a function of the train speed using the current train speed for given by:
wherein fci and k2 are constants based on analysis of actual loadout data; and
New Trim = Base Trim + F(New Speed) where F(New Speed) is the function F(x) using a new train speed for x calculated by the train speed controller.
22. A train loading system as claimed in any one of the preceding claims, wherein the system is arranged such that an increase in train speed is delayed by one car.
23. A train loading system as claimed in any one of the preceding claims, wherein the system is arranged such that a decrease in train speed is applied to a car immediately.
24. A method of loading material onto cars of a train at a mine operation, the method comprising:
reclaiming material for loading onto a train from a material bench at a reclaim rate;
receiving material from the reclaimer in a surge bin, and supplying material from the surge bin to cars of a train that travels under the surge bin, the surge bin including a clam having a trim position controllable to modify an outflow rate of material from the surge bin and thereby a train loading rate of material onto a train, the clam trim position dependent on the train speed such that an increase in the train speed causes an increase in the clam trim position and thereby an increase in the train loading rate, and a decrease in the train speed causes an decrease in the clam trim position and thereby a decrease in the train loading rate;
determining a feed forward train speed based on the reclaim rate, the feed forward train speed being used to set the train speed; and
modifying the feed forward train speed based on the amount of material in the surge bin;
whereby the amount of material in the surge bin is maintained at a level such that stopping of the reclaimer or stopping of the train because of the level of material in the surge bin is avoided.
25. A method as claimed in claim 24, comprising determining the feed forward train speed according to the following relationship between the reclaim rate and the train speed:
Reclaim rate = P * Speed where Speed is the train speed, Reclaim rate is the reclaim rate of the reclaimer, and P is a proportionality constant.
26. A method as claimed in claim 24 or claim 25, wherein determining the feed forward train speed comprises filtering the reclaim rate.
27. A method as claimed in claim 26, comprising filtering the reclaim rate using at least one low pass filter.
5 28. A method as claimed in any one of claims 24 to 27, comprising initialising the step of determining the feed forward train speed to ensure bumpless transfer as the train loading system is switched from manual mode to automatic mode.
29. A method as claimed in claim 28, comprising initialising the step of determining0 the feed forward train speed with an initialisation reclaim rate value determined based on a previous train speed value.
30. A method as claimed in any one of claims 24 to 29, comprising measuring the reclaim rate from the reclaimer using a weightometer.
5
31 . A method as claimed in any one of claims 24 to 30, wherein the step of modifying the feed forward train speed comprises modifying the feed forward train speed based on a difference between the amount of material in the surge bin and an aim bin level indicative of a defined amount of material in the surge bin, wherein a o positive difference between the amount of material in the surge bin and the aim bin level causes the feedback component to positively modify the feed forward train speed and thereby increase the train loading rate and reduce the amount of material in the surge bin, and a negative difference between the amount of material in the surge bin and the aim bin level causes the feedback component to negatively modify the feed 5 forward train speed and thereby reduce the loading rate and increase the amount of material in the surge bin.
32. A method as claimed in any one of claims 24 to 31 , comprising determining the amount of material in the surge bin using a bin level sensor.
0
33. A method as claimed in any one of claims 24 to 32, wherein the step of modifying the feed forward train speed comprises producing a bin level error value indicative of the difference between the amount of material in the surge bin and the aim bin level, and producing a train speed error based on the bin level error value, the
method comprising using the feed forward train speed to modify the feed forward train speed.
34. A method as claimed in any one of claims 24 to 33, comprising applying saturation such that the amount of modification to the train speed is limited.
35. A method as claimed in any one of claims 24 to 34, comprising applying a feedback multiplier such that the amount of modification to the train speed is limited.
36. A method as claimed in claim 35, wherein the feedback multiplier is approximately 15%.
37. A method as claimed in any one of claims 24 to 36, wherein the feed forward train speed used to set the train speed is applied to a train once per train car.
38. A method as claimed in claim 37, wherein the feed forward train speed used to set the train speed is applied to a train at each transition between adjacent cars under the surge bin.
39. A method as claimed in any one of claims 24 to 38, comprising increasing the amount of material in the surge bin prior to a transition of the reclaimer between material benches.
40. A method as claimed in claim 39, comprising increasing the amount of material in the surge bin prior to a transition of the reclaimer between material benches by reducing the speed of the train and thereby reducing the loading rate from the surge bin.
41 . A method as claimed in claim 39, comprising increasing the amount of material in the surge bin prior to a transition of the reclaimer between material benches by increasing the aim bin level, thereby negatively increasing the difference between the amount of material in the surge bin and the aim bin level, reducing the speed of the train and reducing the loading rate from the surge bin.
42. A method as claimed in claim 39, wherein the system is arranged to increase the amount of material in the surge bin prior to a transition of the reclaimer between material benches at a time based on the amount of material remaining in a material bench.
43. A method as claimed in any one of claims 24 to 42, comprising increasing the aim bin level based on material bench type.
44. A method as claimed in any one of claims 24 to 43, comprising determining the clam trim position according to the following equations:
Base Trim = Current Trim - F(Current Speed) where F(Current Speed) is a function of the train speed using the current train speed for given by:
wherein k\ and k2 are constants based on analysis of actual loadout data; and
New Trim = Base Trim + F(New Speed) where F(New Speed) is the function F(x) using a new train speed for x calculated by the train speed controller.
45. A method as claimed in any one of claims 24 to 44, comprising delaying an increase in train speed by one car.
46. A method as claimed in any one of claims 24 to 45, comprising applying a decrease in train speed to a car immediately.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2017901853 | 2017-05-17 | ||
| AU2017901853A AU2017901853A0 (en) | 2017-05-17 | A train loading system | |
| PCT/AU2018/050457 WO2018209385A1 (en) | 2017-05-17 | 2018-05-16 | A train loading system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2018271139A1 AU2018271139A1 (en) | 2019-12-05 |
| AU2018271139B2 true AU2018271139B2 (en) | 2023-09-07 |
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|---|---|---|---|
| AU2018271139A Active AU2018271139B2 (en) | 2017-05-17 | 2018-05-16 | A train loading system |
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| Country | Link |
|---|---|
| CN (1) | CN111164033B (en) |
| AU (1) | AU2018271139B2 (en) |
| BR (1) | BR112019024062B1 (en) |
| CA (1) | CA3063545A1 (en) |
| RU (1) | RU2758169C2 (en) |
| WO (1) | WO2018209385A1 (en) |
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- 2018-05-16 CA CA3063545A patent/CA3063545A1/en active Pending
- 2018-05-16 WO PCT/AU2018/050457 patent/WO2018209385A1/en active Application Filing
- 2018-05-16 AU AU2018271139A patent/AU2018271139B2/en active Active
- 2018-05-16 BR BR112019024062-4A patent/BR112019024062B1/en active IP Right Grant
- 2018-05-16 RU RU2019139998A patent/RU2758169C2/en active
- 2018-05-16 CN CN201880042270.5A patent/CN111164033B/en active Active
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| SU606797A1 (en) * | 1976-08-12 | 1978-05-15 | Государственный проектно-конструкторский и научно-исследовательский институт по автоматизации угольной промышленности "Гипроуглеавтоматизация" | Method of loading loose cargoes into open railway cars |
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Also Published As
| Publication number | Publication date |
|---|---|
| CN111164033B (en) | 2021-08-27 |
| CN111164033A (en) | 2020-05-15 |
| WO2018209385A1 (en) | 2018-11-22 |
| RU2019139998A3 (en) | 2021-08-30 |
| RU2758169C2 (en) | 2021-10-26 |
| RU2019139998A (en) | 2021-06-17 |
| CA3063545A1 (en) | 2018-11-22 |
| AU2018271139A1 (en) | 2019-12-05 |
| BR112019024062B1 (en) | 2023-11-07 |
| BR112019024062A2 (en) | 2020-06-02 |
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