Mine monitoring and control: designing a control room
Effective mine control rooms are critical for safe and efficient underground mining operations, requiring thoughtful design in size, layout, ergonomics, acoustics, lighting, and facilities.
This article outlines essential considerations to optimise the working environment for controllers and support personnel.
A contractor starting a new mining contract at an underground mine undertook to provide and operate a fully staffed mine monitoring and control facility. They engaged personnel, who had no mining experience, and sat them in what was little more than a broom cupboard with their backs to the door, provided a computer with some Excel spreadsheets and a hand held radio…..and called it ‘mine control.’
Sadly, this is an all-too-common scenario. It represents the widespread lack of understanding of the benefits of quality mine control. Previous articles in this series have addressed the role of mine control personnel, support resources required, how controllers fit in the shift management team and where a control room should be located.
This latest article will summarise the technical layout requirements of control room design. It focuses on size and layout, and briefly touches on ergonomics, acoustics, lighting and some of the functional issues that are frequently encountered. Technology is not discussed and is planned to be addressed in a later article.
There is a large amount of very good published material regarding control room design, mostly from other industries. In addition, the ISO-11064 Standard “Ergonomic design of control centres” can be referenced.
The opening anecdote above facetiously references the control room as being the size of a broom cupboard leading to the objective question as to the appropriate dimensions for a control room. The author advocates a minimum control room floor space in the order of 7m x 5m as a rule of thumb. Below this question is addressed in more detail.
How long should a control room be?
‘Long’ in this case meaning the direction along which the desktops of workstations or consoles run. Mines differ in size and complexity and so do the corresponding control rooms. Integrated control rooms may have several disciplines co-located in the one facility thus necessitating a larger floor space.
Many smaller mines will operate a model of having mine control staffed continuously by a single controller. The controller requires a workstation, or console.
- Commonly three or four screens will be arranged across the width of the console.
- A 32” screen is 700 mm wide, so therefore
- three screens will require 2.1m and four will require 2.8m.
It should be noted that ergonomically there should only ever be a single row of screens across a workstation. This is discussed further later.
A second person should be able to sit beside the controller and able to interact with parts of the array of screens. This is important for training, either to introduce a potential new controller or for the controller to receive training. There is also value where close collaboration is required either with operations or maintenance supervisors, trainers or with professional engineering or geology personnel.
To achieve sufficient space the controller’s workstation should be in the order of 2.8 m wide.
In control rooms with a single controller a second workstation is also valuable for shift handover, systems administration and configuration, training and a location for vendor and support personnel when visiting site.
Allowing for two workstations side by side and a passageway to allow movement from in front of to behind the workstations, around 800 mm, requires a total length of around 7 m.
In cases where more workstations are required add 2.8 m to the length for each additional station.
How wide should a control room be?
Width is described as the direction perpendicular to the controller’s workstation/console.
A workstation desktop is typically in the order of 800mm – 900mm. The space required by a controller seated at a workstation is an absolute minimum of 900mm, preferably 1200mm. Allow another 600mm for personal shelves or cupboards and draws behind the controllers work position and another 300mm for attachments, cabling and desk supports.
The width required from a back wall to the front of the workstation is:
900 + 1200 + 600 + 300 mm = 3m
Where multiple rows of controller workstations are required an additional 3m should be added to the width for each row.
Figure 1. Minimum Control Room layout.
An interaction area is recommended in front of the controller workstations, opposite the controller’s position so that visitors can be facing the controllers when in discussion.
This capability also relates to the ergonomic requirements that there should only ever be a single row of screens across a workstation which is discussed later.
The interaction area will require a minimum width of at least 1.5m, possibly a little more.
In addition the video wall with large screens should be mounted on the other side of the interaction area, i.e. opposite from the controller’s console. Allow 300mm for screen mounting.
By this argument the minimum width of the mine control room should be:
3m + 1.5m + 0.3m = 4.8m
Let’s round it up to 5m making our estimated minimum plan dimensions for a mine control room as:
7m x 5m
The vertical axis
Minesite buildings, particularly at remote sites or short lifetime projects, tend to be relocatable and manufactured off site. This type of building typically has a low ceiling height, commonly 2.1m or 2.4m.
Such low ceiling height is a constraint for designing a mine control room in two ways.
A raised plinth (floor) is recommended for the area beneath the controller’s workstations and sitting/standing area and personal cabinet space. The raised floor accommodates ease of providing computer and power cabling. In addition it means that a controller is raised up so that when a visitor who is standing interacts with a seated controller they are close in eye-level.
The plinth should be in the order of 200 – 250mm in height.
The transition from floor level to the plinth should be by a ramp not steps for potential wheelchair access.
Ease of availability and falling prices have made large TV/Video screens a practical medium for setting up a video wall. A ceiling height of 2.4m is a severe constraint in the viability of a video wall. The video wall serves several purposes. It is the source of reference information for discussions between controllers and visitors. Where the control room operates with more than a single controller the video wall is a place to locate shared information thus reducing the amount of material replicated on desktop screens. Video walls can also show key data for discussion between the controllers and visitors, who are located in the interaction area thus reducing the need for visitors to move around behind controller’s workstations.
The video below features the Panama Canal Control room and is a good visual illustration of the key concepts above (note that it is in Spanish). You can also see an example of the same room in this article by Wired magazine.
The video wall appears to be an estimated 4 to 5m in height.
Therefore the minimum dimensions of a control room should be:
7m x 5m x 4.5m
Figure 2. Cross-section.
Growth
The dimensions developed above are the minimum required for mine control alone. Prior to progressing, consideration should be given to other capabilities that could be added or other functions that could be introduced.
A control room very naturally becomes the first point of response whenever there is an incident. As control rooms are typically equipped with backup power and robust communications systems, two important components are already in place. Should the control room serve as incident control in any kind of emergency, what additional space will be required?
Another question to ask: as operations mature and additional monitoring technology is added, such as ventilation on demand, pump control, paste fill etc. Will the control room have sufficient space, particularly the video wall, to accommodate the additional monitoring?
Also consider having space for controllers to stretch and have some form of exercise. The author has seen a control room with stools that have built in exercise cycles and another with a treadmill.
Entrance
Imagine walking into a hotel check-in expecting to see the smiling faces of the clerk either serving people or waiting to serve you. However imagine instead being faced with the clerk, or clerks, working, seated or standing, facing away from you, all you see is their backs.
On the other hand, we all know what it is like working with intense concentration at a desk which is up against a wall then someone approaches you from behind, looks over your shoulder and catches you by surprise.
ISO 11064 standard is quite specific on this issue:
4.2.1.1 Entrances/exits
Entrances and exits should not be positioned behind the control room operator (see 4.3.3). ISO-11064-3-1999
The Panama Canal Control Room is an example where the entrance is located at the end of the video wall and upon entry visitors are immediately located in the interaction area in front of the controllers.
The passageway for moving from in front of, to behind the controllers’ workstations should be situated as far from the entrance as possible.
Windows
Two applications of windows to a control room can be identified:
- External windows that provide line of sight to parts of the operation being monitored and controlled. External windows only apply when the control room is located at the mine site.
- Windows providing a view into adjoining spaces as a source of information.
In open pit mines external windows can variously provide mine control views of:
- the whole pit
- key haul roads
- dumping locations
- the workshop go-line and no go-line.
In underground mines external windows can provide mine control with views of the:
- tag board (often located across a passage/walkway from mine control)
- winder headframe
- surface dumping
- surface stockpile
- surface workshop go-line and no go-line.
With external windows it is important to consider the impact of orientation in relation to the sun.
A large open pit iron ore mine in Western Australia (Southern Hemisphere) had a well-appointed mine control/dispatch facility on a hill overlooking the pit where the whole mining operation could be seen through large windows. The hill was located on the southern side of the pit so the large windows face north. This meant that for large parts of the day the sun was shining directly into the windows resulting in the controllers being unable to see anything. Blinds were introduced which negated the benefit of being able to see the operation.
Windows that provide controller personnel with views into adjoining spaces provide a different role. Typically, there will be a sliding window with a counter arrangement of some sort, where face-to-face communication can occur between a controller and somebody external to mine control without the visitor entering the control room. Arrangements of this nature work well when the mine control room adjoins the muster room or in underground mines in cases where there is a passage leading to the shaft, or to where vehicles are parked, that passes beside the control room.
A word on video walls
There have been cases where the video wall provides the working screens for controllers, i.e. they are working from the video wall display rather than desktop displays. This is particularly useful when discussing a situation and the controller simply throws up one or more displays to the video wall for another controller or engineer or visitor to see what’s being described without crowding around a small screen.
A video wall should be directly in front of the controller’s work position. Having controllers look to the side for information on screens should be avoided.
It is essential that the video wall displays are scaled to enable controllers to read them comfortably from their console locations. This is achieved by a combination of the video wall screen size and the width of the interaction area.
Most importantly a video wall in a control room is for the use of the controllers. It is not there to allow managers to show off to visitors. The very large screens used in some integrated control rooms often have little practical purpose.
Ergonomics
Control room personnel tend to work long continuous hours with limited opportunity for breaks. Therefore, ergonomics are important. There is extensive literature available regarding ergonomics and particularly ergonomics for control rooms. This discussion will not attempt to cover the field but will address an important issue.
This author strongly advocates that there should be a single row of screens on workstation.
Second and third tiers of screens are ergonomically bad resulting in neck issues. Also from a practical point of view the higher tiers of screens block line of sight to a video wall and limit the controller’s vision of visitors facing them.
Figure 3. Controller working on a video wall.
Good quality chairs are essential. Control room personnel are seated for many hours and literally hot seat at each shift change. Chairs should also be regarded as consumable items that need to be maintained and replaced regularly. One of the most common failures is the castors, rubber wheels in place of the castors can serve to mitigate the problem.
Foot stools are essential for controllers working in a seated position.
Sit-stand desks have become common and do serve to alleviate some of the ergonomic issues.
There is a tradeoff between the use of sit stand desks and the idea of a continuous bench, or counter, top. The continuous arrangement allows for the bench top to be supported by cantilevered legs thus allowing the controllers to roll along between workstations particularly for collaborative situations. A continuous bench needs to be a fixed height so cannot be adjustable in the manner of sit stand desks.
Acoustics
Regardless of the level of automation of systems there is always a need for voice communication in a mine control room - either with other people face-to-face within the control room or externally by phone or voice radio.
Noise mitigation is important to enable voice communication. There are a several different design considerations that can assist.
- By using headsets for individuals to take incoming radio calls the sound level is reduced. Typically, cordless headsets are used with a single headphone and a stalk microphone. A button hangs from the headset to enable transmission. Newer open-ear headphones designed for exercise show significant promise for both comfort and in room awareness.
- Removing computers from the control room to a separate server room largely eliminates the ambient noise associated with cooling fans. All communications equipment should be located in the server room.
- The use of rubber wheels on chairs reduces noise but has other benefits including robustness and being less damaging to floor coverings, particularly important when a raised plinth is used.
- Air conditioning and heating systems should be chosen to minimise noise. Through the wall air conditioners are not suitable, split systems or ducted systems are quieter.
- Invariably there will be large flat reflective surfaces in a control room such as the video wall, ceiling, whiteboards, walls and floor. Further reduction in ambient noise can be achieved by using dampening covers on some of these surfaces, such as cork pin boards on walls, or acoustic carpet tiles on ceiling and walls.
Lighting
The industry literature regarding control room design clearly recommends using downlights only in control rooms to avoid reflection from screens.
Prefabricated buildings that are often used to house mine control rooms have lighting fixtures mounted against the ceiling such that they protrude, and the light source is a small distance below the ceiling. This result in a direct line from the light source to the reflective surfaces of computer or video screens and so impeding the view.
Where external windows allow natural light, the lights should be dimmable.
Facilities
Air conditioning and heating should be mandatory and able to be controlled from within the control room. The control room should be an air conditioning zone in its own right.
Where a control room has a single point of entry and exit that is internal from a larger building then an alternative emergency exit should be considered.
A control room continuously supports the operations process therefore must be able to run continuously. Computers, communications infrastructure and lighting all require electrical power. A backup power supply is essential for mine control along with power for the communications infrastructure that enables mine control to remain in touch with the operation during outages.
External factors
Control room personnel require easy access to some form of kitchen facility. Controllers work long hours and often it is inconvenient for controllers to leave their station for any length of time. There may be a temptation to locate kitchenette facilities within the control room; however, caution should be taken:
A mine control room for a remote underground mine site was designed and constructed off site for transport to the remote location. The design was for the control room to be an extension to the existing mine operations building located against the passageway used by all miners from the shower block and lockers to the shaft.
To accommodate the requirement that controllers be able to prepare refreshments during their shift a small kitchen lunchroom was incorporated into the design located at the end of the control room furthermost from the door to the passageway. Unfortunately, the designers were not aware that the building had no other kitchen or refreshment facilities.
This resulted in a steady stream of visitors, particularly at shift change, entering the control room solely for the purpose of getting a cup of coffee. Thus, unnecessarily distracting from the operation of mine control.
Similarly, access to bathroom facilities is essential and should be near mine control, particularly where the controller is a single person role. The bathroom entrance should be external to the control room but can be either dedicated to mine control or a common facility.
Consider an underground mine with a surface control room, it is probable that on night shifts the controller could be the only person on the surface. The ability to easily visit the bathroom is essential and should be a safety consideration.
Technology infrastructure
This discussion does not attempt to address the technology infrastructure required for successful mine control apart from a comment that the technology used needs to be good quality, well installed and conscientiously maintained.
An interesting occurrence occurred regularly in the mine control room at a remote mine site. Whenever a controller got up from their seat, all the screens on the video wall went blank.
The control room had been constructed off-site from two containers and shipped to site for installation. As part of the offsite build the control room was pre-wired with all cabling in conduits.
An investigation concluded that the cause of the video wall screens going blank was related to having both data and power cables laid in the same conduits, contrary to the design requirements.
Conclusion
Designing an effective mine control room contributes to ensuring the safety and efficiency of underground mining operations. This involves careful consideration of various factors such as size, layout, ergonomics, acoustics, lighting, and facilities.
By adhering to industry standards and incorporating best practices from other sectors, mining companies can create a control room environment that enhances the performance and well-being of control personnel.
Ultimately, a well-designed control room not only improves operational efficiency but also contributes to a safer and more productive mining operation.