emissions management for coal...

Emissions Management For

Coal Handling

Neptune Bulk Terminals Emissions Management

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Contents

Emissions Management for Coal Handling ............................................................................2

1) Audit of Loaded Coal Trains On Arrival....................................................................2

2) Assessment of Risk Prior to Unloading Trains .........................................................3

3) Management While Unloading Trains .....................................................................4

4) Management of empty coal Cars Departing the NBT Site ......................................5

5) Management of Conveyed Coal ..............................................................................7

6) Management of Coal in Stockpile ............................................................................9

7) Management When Reclaiming Coal from Stockpile to Vessel ..............................13

8) Management of Vessel Emissions ...........................................................................13

9) Management of Site ................................................................................................13

Appendix 1 .............................................................................................................................16

Appendix 2 .............................................................................................................................22


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Emissions Management for Coal Handling

Neptune Bulk Terminals (NBT) is a participant in the logistics and supply chain for the export of

metallurgical coal from British Columbia and North East Alberta. With respect to emissions, NBT

has a key role in auditing the performance of certain aspects of the supply chain. This includes

ensuring that we demonstrate excellence, continuously improve our performance and actively

seek and invest in technology and training that allows NBT specifically, and the entire supply

chain generally, to perform better than or at the requirements of the respective emissions

permits.

NBT’s Environmental Management, Quality Management, Safety Management systems and

Emergency Management Response Plan provide the tools to audit performance, identify and

prioritize action items, respond to system failures and internal and external concerns, and to

manage emergencies related to emissions created through operational activities involved in the

handling of coal. This Emissions Management document outlines the current emission controls

relating to the coal handling system. The key NBT activities with respect to emissions

management are:

1) Audit of loaded coal trains on arrival

2) Assessment of risk prior to unloading trains

3) Management while unloading trains

4) Management of empty coal cars departing the NBT site

5) Management of conveyed coal

6) Management of coal in stockpile

7) Management when reclaiming coal from stockpile to vessel

8) Management of vessel emissions

9) Management of site

1) Audit of Loaded Trains On Arrival

The top of every coal car of every train entering the NBT site is recorded by a camera. The

recordings for twenty-five trains, five trains from each TECK mine, are inspected by an

independent third party each month. The third party provides an analysis of the volume of coal

in the car to confirm loading was below the sill height and the appropriate profile in the car was

achieved to prevent wind loss. The third party also provides an analysis of the performance of

the crusting agent which is applied at each mine load out and again near Kamloops, BC.


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Figure 1 – Coal car properly profiled; loaded below sill with intact crust.

The third party analysis is provided to TECK Logistics each month and shared with each source

mine, re-enforcing successful outcomes and addressing any issues with regards to car loading

or the application of the crusting agent. On arrival, and at unload point, at NBT all coal trains

are inspected for the integrity of the crust and the height of the coal in the car by terminal staff

and operators. Discrepancies are reported to the TECK Logistics group for action by the

originating mine.

2) Assessment of Emissions Risk Prior to Unloading Trains

The NBT operating group reviews all available information provided at the time of the train

loading and establishes an unloading plan for each train to stockpile or direct loading to vessel.

Considerations in the plan include safety, emissions control and mitigation, noise control and

mitigation, productivity and cost control. The required control tools are determined on the

basis of this assessment; these include, pre-unloading car water addition, dumper scrubbing

system, water systems at the coal dumper, water addition on conveyors, spray systems on

stackers, spray pole systems, ground water cannons, crusting agent systems for stockpile and

empty cars and on-site weather stations. Having determined which tools are required these are

verified to be available for use prior to unloading.

For the purposes of managing emissions, the coal loaded to each train is sampled for its

moisture content. The mine provides the moisture content of the coal to NBT within 24 hours

of departure of the train from the mine. If the moisture of the coal is not in the target range,

and presents a risk of creating dust when unloading at NBT, each railcar has water added at a


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prescribed, measured rate 100m ahead of the NBT unloading station which is referred to as the

“dumper”. Trains can be travelled under this spray system multiple times should this be

required to achieve a desired moisture level.

3) Management of Emissions While Unloading Trains

The rotary coal car dumper is an enclosed building with an air collection and wet scrubbing

system. The system runs continuously while rail cars are unloading, creating a negative

pressure in the unloading building. All collected air is then forced through a wet scrubber

which removes particulate; the air is then released via a single stack. The collection system has

complete redundant fan and motor to allow continued operations in the event of a mechanical

failure. In accordance with the air emissions permit, emissions from this stack are audited and

measured by third parties and by trained NBT personnel on an ongoing basis. Water from the

scrubbing system is treated to remove collected particulate.

Figure 2- Wet scrubber at coal dumper.

The wet scrubber is connected to the NBT industrial technology system Rockwell Software

Supervisory Edition (RSSE) which allows for continuous monitoring and recording of its

operational, mechanical and electrical status. NBT personnel are trained to observe and report

any occurrences of unusual emissions from the stack point or the dumper building as part of

their standard work routine. An NBT employee is stationed at the dumper at all times while

unloading is occurring. Manual spray systems are available should any coal dust be observed to

escape the building. These are rarely used.


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Figure 3 - Scrubber Screen RSSE

The two or three locomotives that remain attached to the train through the unloading process

are in idle mode and not under load, greatly reducing emissions. NBT trains are moved using an

electrically driven car indexer. NBT personnel are trained to observe for and report any unusual

performance issues including: emissions, noise, fluid leaks or damage as the idling locomotives

move through the coal dumper.

4) Management of Emissions for Empty Coal Cars Departing the NBT Site

Once a car has been rotated and unloaded in the dumper, then returned to the upright

position, it is weighed to ensure that no significant amount of coal remains in the car and will

be carried back to the mine, potentially releasing dust from the car as it travels. Should the car

weight exceed the set point, it is visually inspected for the cause of the carry back and if it is

coal, the car is unloaded until all the material has left the car.

All cars are visually inspected as they leave the coal dumper and a photo recording of each car

interior is captured and stored.


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The exterior unloading side and top sill of

each car is washed prior to leaving the NBT

site to ensure no residual coal or coal fines

leave on the car after it is unloaded. This

water is collected and treated to remove

any coal.

Currently, Neptune is implementing, as a

trial program, a binding agent spray system

for empty coal cars before they are returned

to the mine. Once emptied, coal cars have a

bio-degradable, environmentally-friendly

binding agent sprayed into the interior,

similar to the product used to crust the

loaded cars when departing the mine. This

binding agent ensures no coal can leave the

car on the return journey.

The performance of the binding agent is

monitored through the random use of on-

board cameras and portable particulate meters. This system is being further enhanced by being

linked to a weather station to ensure optimal application of the binder to the temperature and

humidity at the time of unloading.

Figure 5- Binder being applied to empty coal car.

Figure 4- Car washing system cleans residual coal from sills of coal car after dumping.


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5) Management of Emissions for Conveyed Coal

The NBT conveyors are designed and operated with ample room to prevent coal from coming

close to the edge of the conveyor and adjust to the distribution of coal on the conveyor to

prevent spillage. The enclosed transfer chutes permit coal to move from one conveyor to

another without generating dust. The chutes are designed to optimize the flow of the coal,

minimize the entrainment of air in the coal flow which prevents dust from being lifted out of

the product and to have no spillage by centering the transferred coal on the next conveyor

belt. Transfers are designed with internal water spray systems to permit “self” cleaning and

prevent plugging which could cause spillage and dust emissions.

Four additional controls are also employed to mitigate coal dust emissions from conveyed coal:

a) Scrapers: Scrapers are used to remove residue from the conveyor belt and are situated near

the head pulley of a conveyor as the coal is discharged to the next system. All conveyors

have been fitted with secondary scrapers to back up the work of the first. This prevents

particulate from falling from the return side of the belt and becoming air borne.

Tension in the scraper mounting mechanism allows the scraper to self-adjust to

compensate for wear. Scraper blades are regularly replaced as a part of the planned

maintenance program.

b) Conveyor Belt Misalignment Correction: From time to time, a conveyor belt may move out

of alignment. This is known as ‘side travel’. If the side travel becomes excessive, minor

temporary spillage of coal product could occur on site. All the conveyors are fitted with

automatic side-travel correction devices which lead the belt back on to its designed track.

In the event that the side travel overcomes these tracking devices, there are side travel

sensor switches which detect excessive movement which automatically shut the conveyor

down triggering further investigation by the maintenance department.

c) Spillage Protection: Each Conveyor has plugged chute detectors, spill detectors and rip

detectors, any of which will shut-down the conveyor if they are tripped. The plugged chute

detectors are of a tilt switch design which trip as soon as coal in the chute backs-up to the

point that the switch is displaced from a vertical position. The sill detectors are a balance

device deployed at the head-end of a conveyor and provide a back-up to the tilt switches.

All conveyors are electrically interlocked together. This ensures that if any one conveyor is

stopped then all the following conveyors in the sequence also stop in order to prevent

over-load and spillage. Belt rip detectors provide an early warning of objects penetrating

the belt which may cause damage to the belt and spillage to occur.


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d) Skirts: Each conveyor transfer is equipped with a set of skirts where the product feeds onto

the next belt. This ensures the product centres onto the belt and prevents spillage.

There is constant observation of the stockyard, conveyors, stacking and reclaiming equipment

by onsite employees, supervision and cameras recording the performance of the system during

the conveying of coal from the dumper to stockpile to direct to vessels. If emissions are

observed during the conveying of coal to stockpile or while loading a vessel, additional water is

added at a prescribed, measured rate from a weir located above the conveyor prior to entering

the stockyard, at the stacking point, at the incline of the conveying system leaving the stockyard

and at both ship loaders.

Planned water addition also occurs at these points based on field data collected from the coal

when it has been in stockpile. If the moisture level is below the known safe reclaim point,

water is added to ensure no dust occurs during handling.

Figure 6 - Binder applied to stockpiled coal.

A second system is installed on the first conveyor from the dumper which adds a binder, similar

to the crusting agent added at the load point and to the interior of the empty coal cars as they

leave site. The binder is added to coal being stockpiled if it will be on site for periods of weather

conditions where the temperature is below zero degrees or above 25 degrees Celsius, or in the

case of water restrictions.


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Figure 7 - No dust while stockpiling at below zero temperatures. Note ice in foreground.

The standard operating procedure dictates the stacking equipment operate as close to the pile

as safely practical which minimizes drop height and reduces the entrainment of air in the

product flow which can produce dust. Water addition at the point of stacking occurs as routine

operating procedure which ensures that any dust entrained in the coal flow from the stacker to

the stockpile is contained and “knocked down”.

The standard operating procedure dictates the reclaim equipment operates with its bucket in

the pile. During routine operation, a fine mist of water is added as the coal is reclaimed to

ensure no dust escapes when the coal arrives at the first reclaim belt.

6) Management of Coal in Stockpile

The coal stock yard has a capacity for up to 600,000 metric tonnes (MT) in the summer months

and approximately 550,000 MT in the winter months. This volume difference is a result of the

safe height the coal can stacked at and not slough. In wet winter conditions, there is a greater

risk of pile slough.

In both warm and cold dry conditions, the Neptune site is manned 24 hours a day with

personnel dedicated to ensuring optimum conditions and system performance are occurring in

the coal stockpile storage area. The Neptune site is manned for stockpile management on

required days normally prohibited from operation under the Collective Agreement. This

includes twelve 8-hour Union Meeting nights per year, New Year’s Day, Labour Day and

Christmas Day.

NBT prevents dust from leaving the coal stock yard through the use of:

A. Coal moisture content as described in the previous five sections.


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B. Stockpile configuration; Neptune limits the number of stockpiles reducing the number

of exposed surfaces. The stockpiles are constructed longitudinally NE to SW on either

side of the stacking/reclaim berm way. This provides for limited exposure of surface

areas to the prevailing winds. (See image next page)

Figure 8 - Neptune Coal Stockpile viewing North.

C. Stockpile height and profile: wherever possible, Neptune limits the height of the

stockpile and ensures the piles are either stacked flat or flattened through the use of

mobile equipment, which prevents excess turbulence from occurring in the air flow.

D. Moisture addition to pile surfaces which prevents particles from becoming air borne.

NBT has five independent methods of water application to ensure the surface of the stockpiled

coal does not dry out and that redundant wetting capacity is in place should one system suffer

a failure.

a) The primary water application system is the fourteen stockpile spray poles located

around the perimeter and in the interiors of the stockpile. These poles have both

misting and individual water cannons on the top of the pole.


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Figure 9- RSSE Spray Pole Overview

The high mast misting spray bars poles have both a manual and automatic

capability. The automatic program is based on an algorithm which works from data

from three on-site weather stations which measure wind direction, humidity and

temperature. The computer program uses the algorithm to turn water on to the high

mast misting spray bars and ensure maximum application of water to the stockpiles

as required by the weather conditions occurring. Greater detail technical detail is

provided in Appendix 1 and 2 of this document with regards to the Spray Pole Dust

Control Automation.

The water cannons on the spray poles are manually operated through the RSSE

system and are used for moisture addition as well as wetting the tops and upper

sides of stockpiled coal.

b) The two stacker reclaimers are used to apply water to the surface of the stockpiles

from the center of the stock yard to their maximum reach. The two machines can

cover the entire length of the stock yard in approximately 45 minutes if operated

individually and in 30 minutes if operating simultaneously while applying the

required amount of water in the form of a mist to ensure the pile surfaces remain

wetted. There is a clear process in and demonstrated history of using these

machines for pile wetting in priority to stockpiling or reclaiming coal should the

weather and stockpile conditions require this step. These units can operate in wind

speeds of up to 40 km/h above which they must be shut down for safety reasons.


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c) The fourteen spray poles have manually operated water cannons at the base which

can provide a water spray over 70% of the maximum pile surfaces and the exterior

base of the entire stock yard.

d) There is access to water the entire length of the berm which runs through the centre

of the coal stock yard and down the entire length. A number of specialized water

cannons have been built and are used to provide coverage to 70% of the stockpile

surfaces from the interior of the stockpiles. This provides a substantial overlap to the

water cannons described in point three above and allows for 100% pile coverage

between the two means of pile wetting.

Figure 10 - showing reach of portable water cannons.

e) There is one water truck on the Neptune site equipped with a turret style water

cannon on its front bumper. This unit can travel the length of the centre berm or

around the base of the coal stockpiles as required. It provides coverage to isolated

spots or in areas where individual water cannon maybe temporarily out of service.

The five methods of pile wetting provide a combination of abilities such that should any two

methods be out of service full stockpile coverage can be maintained at all times.

As with all environmental control systems at NBT, maintenance of these systems is a priority.


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7) Management When Reclaiming Coal from Stockpile to Vessel

In addition to the ability to increase the moisture content of the coal prior to and during ship

loading, the conveyors and ship loaders have specific enhancements to assist in controlling coal

dust and potential emissions. These include spill trays, tail pulley curtains and water addition in

the ship loader loading spouts.

The yard conveyors travel from the stockpile area to a surge bin, an elevation gain of

approximately 30 meters. Catchment trays have been installed under these conveyors at the

elevated point to ensure no material falls from the conveyors or the return side of the belts and

becomes air borne.

These trays have an automatic wash feature which ensures material build up is minimal and the

collected material is kept wet. The two coal ship loaders have a similar collection system but,

rather than a tray, a secondary conveyor belt has been installed under the primary conveying

system on the ship loader shuttle. These secondary conveyors catch any material that could fall

from the primary conveyor for vessel loading and the return side of the primary belt as well.

This prevents material from becoming air borne, and this material is collected and returned to

stockpile.

Both coal ship loader spouts have water addition points to permit wetting of the coal should there be dust occurring at the vessel hatch. The ship loaders are manned at all times during vessel loading and operators are trained to look for, report, and mitigate dust occurring during vessel loading. 8) Management of Vessel Emissions

As a member of Green Marine, NBT actively encourages all vessels visiting the terminal to participate in the PMV initiative to have marine vessels use the highest quality lowest impact fuels available. On arrival, all vessel personnel meet with terminal staff and, as part of the loading agreement, sign the requirement not to operate the main vessel engines. Ship loader operators and foreman report any breaches of this agreement in a timely manner. Neptune has the power and distribution system to supply bulk vessels with shore-based power should bulk vessels with this capability become available.

9) Management of Site

In addition to the detailed management processes described above, there are site processes which assist in the management of emissions: site cleanliness, spills, mobile equipment, air quality monitoring, training and awareness.


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Site cleanliness is managed through the operations group. By site design, the coal system (the rail track, unloading system, stockpiles, loading systems and ship loading) is contained as a separate unit. All water in this area drains to the coal water management plant. Spills of coal on site are uncommon and are cleaned up at the time they occur. Spillage can only occur adjacent to or amongst operating equipment and presents a trip/slip and fall hazard to employees, in addition to the possibility of allowing coal to become air borne. All spilled material is collected and returned to stockpile. All required maintenance services have been positioned to service the coal system such that mobile equipment does not have to leave the stockpile area. Access into the storage area is limited to a single road way, thus reducing traffic. A number of speed bumps and water swales are in place to ensure light vehicle traffic is not tracking coal out of the coal area. Road ways are routinely washed using the water truck and power swept throughout the year. All mobile equipment is purchased to meet or exceed current emission standards. NBT has been aggressive in ensuring it is a leader in the port community with respect to meeting California Tier 3 standards or better for all its large and small mobile equipment.

Figure 10- Onsite air monitoring and particulate measurement.

Neptune has onsite air monitoring and particulate measurement devices that exceed permit requirements. Operations and maintenance personnel are included in the investigation process, follow up and corrective actions required should these devices indicate any recording near permit exceedance levels.


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There is ongoing training and education of all employees with regards to safety and the environment, including emissions.


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APPENDIX 1

Neptune Bulk Terminals Limited

Spray Pole Dust Control Automation

Quick Reference – Part 1

QCA Systems Limited Spray Pole Dust Control Automation Reference Manual

Nov 27th, 2013 Page 0




Version: 1.0 Date: Nov 27, 2013



Contents

1. System Overview ....................................................................................................... 2 1.1. RSView Screens .............................................................................................. 2 1.2. Weather Monitoring Stations ............................................................................ 2 1.3. Dust Control Program ...................................................................................... 2

Weather Station 1 Calculated K Value: .......................................................................... 3 Group 1 Mist Times ........................................................................................................ 3



1. System Overview

The spray pole dust control system is a distributed control system which allows centralized supervisory manual and automatic control of the spray poles.

Coal storage dust control is provided by spray poles positioned around the stockpiles. The spray poles provide two types of moisture addition. One is a fixed array of misters connected to a horizontal manifold sitting a top the spray pole. The second is a single nozzle or turret which directs a spray similar to a fire hose. Both types of sprays are used to prevent the piles from drying out.

The turrets operate with manual intervention locally at the spray poles or remotely via the supervisory HMI system. The fixed misters are able to run in manual or full auto mode. The full auto mode turns the misters on and off using a weather based algorithm and RSView timer setpoints. Three site weather stations provide data to the system.

1.1. RSView Screens

RSView supervisory control system screens are used to control the spray pole system. On and off timers can be altered, automatic weather setpoints can be adjusted and the entire system can be monitored remotely.

1.2. Weather Monitoring Stations

There are three weather stations located around the coal system; the maintenance building, coal dumper and Tower # 32.

Humidity, temperature, wind speed and direction are used to determine which mists are going to be used to control the main PLC program.

1.3. Dust Control Program

The automated math algorithm output has been named the K factor. This control

scheme attempts to estimate coal moisture. Users have the ability to set K parameters

for each pole. The K factor control scheme uses weather station data:

Wind speed

Wind direction

Humidity

Temperature

Rain fall (interlock only to prevent overwatering)



Weather Station 1 Calculated K Value:

K=SQRT{ [(Temperature^2)*Wind Speed]/Humidity}

Temperature: in Fahrenheit

Wind Speed: in Mph

Humidity: in percent

Compare this computed value to the Normal and Extreme K value settings for each Spray Pole for specified wind directions

Example, where:

Temperature: 68 F

Wind Speed: 10Mph

Humidity: 70%

K = SQRT {[(68^2)*10] / 70} = 25

Group 1 Mist Times

If Weather station 1 calculated K value is greater or equal to weather station 1 normal K

value set point, Group 1 mist time:

Group 1 Mist On Time (sec) = Group 1 Manual Mist On Time (from RSView – e.g. 15 seconds) + 2(sec)*( K calculated-K normal weather station 1 setpoint)

Example, where:

K normal setpoint = 18

K calculated = 25

Mist On Time setting (sec) = 15

Group 1 Mist On Time (sec) = 15 + [2 * (25 – 18)] = 29

*** End of Document ***

Neptune Emissions Management

Nov 27th, 2013

APPENDIX 2









Version: 1.0 Date: Nov 27, 2013



Contents

1. System Overview ....................................................................................................... 2 1.1. RSView Screens .............................................................................................. 2 1.2. Weather Monitoring Stations ............................................................................ 2 1.3. Dust Control Program ...................................................................................... 2

Weather Station 1 Calculated K Value: .......................................................................... 3 Group 1 Mist Times ........................................................................................................ 3 Accumulated Rainfall ..................................................................................................... 4 Humidity ......................................................................................................................... 4 Temperature .................................................................................................................... 4 Wind Speed ..................................................................................................................... 4 Wind Direction ............................................................................................................... 4 Auto Mist Times ............................................................................................................. 6



2. System Overview

The spray pole dust control system is a distributed control system which allows centralized supervisory manual and automatic control of the spray poles.

Coal storage dust control is provided by spray poles positioned around the stockpiles. The spray poles provide two types of moisture addition. One is a fixed array of misters connected to a horizontal manifold sitting a top the spray pole. The second is a single nozzle or turret which directs a spray similar to a fire hose. Both types of sprays are used to prevent the piles from drying out.

The turrets operate with manual intervention locally at the spray poles or remotely via the supervisory HMI system. The fixed misters are able to run in manual or full auto mode. The full auto mode turns the misters on and off using a weather based algorithm and RSView timer setpoints. Three site weather stations provide data to the system.

2.1. RSView Screens

RSView supervisory control system screens are used to control the spray pole system. On and off timers can be altered, automatic weather setpoints can be adjusted and the entire system can be monitored remotely.

2.2. Weather Monitoring Stations

There are three weather stations located around the coal system; the maintenance building, coal dumper and Tower # 32.

Humidity, temperature, wind speed and direction are used to determine which mists are going to be used to control the main PLC program.

2.3. Dust Control Program

The automated math algorithm output has been named the K factor. This control

scheme attempts to estimate coal moisture. Users have the ability to set K parameters

for each pole. The K factor control scheme uses weather station data:

Wind speed

Wind direction

Humidity

Temperature

Rain fall (interlock only to prevent overwatering)



Weather Station 1 Calculated K Value:

K=SQRT{ [(Temperature^2)*Wind Speed]/Humidity}

Temperature: in Fahrenheit

Wind Speed: in Mph

Humidity: in percent

Compare this computed value to the Normal and Extreme K value settings for each Spray Pole for specified wind directions

Example, where:

Temperature: 68 F

Wind Speed: 10Mph

Humidity: 70%

K = SQRT {[(68^2)*10] / 70} = 25

Group 1 Mist Times

If Weather station 1 calculated K value is greater or equal to weather station 1 normal K

value set point, Group 1 mist time:

Group 1 Mist On Time (sec) = Group 1 Manual Mist On Time (from RSView – e.g. 15 seconds) + 2(sec)*( K calculated-K normal weather station 1 setpoint)

Example, where:

K normal setpoint = 18

K calculated = 25

Mist On Time setting (sec) = 15

Group 1 Mist On Time (sec) = 15 + [2 * (25 – 18)] = 29



Accumulated Rainfall

Accumulated rainfall is currently recorded using the weather station. This data is used to

lock out automatic mister operation if it has recently rained. This is done to prevent water

being unnecessarily added to the piles. Rainfall is recorded in mm.

Humidity

Relative humidity is used in the automated control of the Misters. This data is recorded

in percent. This value is used in the K value calculation. It is assumed that rainy

conditions result in increased humidity.

Temperature

Temperature is used for the Mister Auto mode control. This value is used in the K value

calculation. The K value calculation uses temperature in Fahrenheit units. All references

to other temperature readings in the RSView system are in Celsius.

Wind Speed

Wind speed is a key input for automated control. Windy conditions are utilized to carry

the water to the coal piles effectively.

Wind speed is used in the K factor approach. Wind speed is recorded in mph. Extreme wind conditions are defined as speeds above 35 mph, when ship loading is stopped. Filtered average speeds are used in order to reduce solenoid valve fluctuations in short gusts of wind or breaks in the wind.

Look up tables are used to configure mist control for individual poles. Look up tables are a mechanism that is used to configure and control the system. Each mister has its own look up table that determines the K value for pole operation based on wind direction. Each look up table is a matrix of rows and columns representing wind direction quadrants and wind speed levels respectively. At each intersection we define whether the mister is on or off.

Misters are automatically turned on when the calculated K value exceeds the value of the look up table.

Wind Direction

The wind direction is utilized to place water onto the piles effectively. The user has the ability to select wind directions for each pole. This enables misting for that pole when certain conditions are met using the K factor approach.

Wind direction is presented using look up tables for each pole. An RSView screen allows the user to enable misting for a pole based on wind direction at a preset K value.

For poles located at the north end of the coal piles, these sprays function to trap coal



dust as a last defence. For this reason, two K factor thresholds are provided. The first is defined as normal wind conditions and the second as extreme.

Screenshot from RSView: Look up table for Spray Pole ‘B’



Auto Mist Times

Auto mist times are derived from the manual mist times for each group. When conditions

produce a calculated K value (shown in RSView as “Current K Value”) which is less than

the normal K set point, the manual mist timers are used for poles within that grouping

regardless of wind direction.

For values between the normal and extreme K set points, poles mist based on wind

direction that is set in RSview for each pole. The current manual mist times for each

group apply to each group as follows:

Two seconds are added to the Mist on time for each calculated K value above the

Normal K set point. The Mist off time is a slope calculation done in the Control PLC. It

uses the Mist off time as entered for the manual mist off times for each group. The Auto

mist off time is formed by subtracting time away until the mist off time is zero when the

Extreme K set point is reached.

Ex.

Manual Mist On time = 45s, K normal = 25, Current K value = 30s.

Auto Mist On time = 45s + (30-25)*2s = 45+10 = 55 seconds

A slope calculation is used to determine the mist off time. The line is calculated from the

Normal K value which represents the manual Mist Off value and the line crosses at the

Extreme K set point. This turns the mist on fully and remains on until the current K value

drops below the Extreme set point.

The user can fine tune the Auto system by selecting a manual mist on and off time and

choosing appropriate K set points after some experimenting. Spacing out the Extreme K

set point results in a less aggressive mist cycle that delivers less water as apposed to a

closer spaced set up.

Note the slope is calculated using the weather station #1 data. The slope calculation

applies to all poles regardless off additional weather stations.



Screenshot from RSView: Timer adjustments.



Typical K values

Typical Mister Operation within the K value range. The following illustration assumes a K

normal value of 20 and an Extreme value of 30.

Some K values are included for reference under set conditions.

K value with temperature varying

Variable TemperatureRel H = 70%

Wind Speed = 7 mph

0

5

10

15

20

25

30

35

-10 -5 0 5 10 15 20 25 30 35 40

Temperature (C)

K

20 30 40 500K Value

Low Moderate Extreme

60

Manual

timer

Utilized

Mister

On

Continuously

K>Extreme

set point

Mister On

based a slope

calculated

time



K Value Wind Speed Variable

K Value Relative Humidity Varying

*** End of Document ***

Variable Wind SpeedRel H = 70%

Temp = 20 C

0

10

20

30

40

50

0 5 10 15 20 25 30

Wind Speed (mph)

K

Varying Rel HumidityWind Speed = 7 mph

Temp = 20 C

0

50

100

150

200

250

300

0 20 40 60 80 100 120

Relative Humidity (%)

K

emissions management for coal...

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