GM/SSE Capcoal Surface Operations
Business Improvement Specialist, Anglo American – Capcoal Open Cut
Control Systems Coordinator, Anglo American – Capcoal Open Cut
Bunds are a safety critical control in open pit mining to prevent and mitigate risks associated with heavy vehicle operations. Between 2014-2019 at Capcoal Surface we have had 14 incidents and in Queensland 2012 – 2018, 47 incidents where bunds have stopped uncontrolled vehicles and prevented potentially fatal injuries. At Capcoal we have 100km+ of bunds in the pit, with more than 50 heavy vehicles interacting regularly. Currently the process to monitor & audit the compliance to standard is made via visual inspection with no quantitative process or records.
In a collaboration with SICK sensors we developed a system using laser sensors to scan the bunds and provide a comprehensive measurement including not only height but:
Roadside facing batter angle.
Width at the top, if applicable, trapezoidal bunds.
Distance to high-wall.
Data is transmitted via ethernet to a central data collection system called TDC which then generates a heatmap and a report identifying sections of bund requiring intervention and their criticality.
Some of the benefits of this development, besides measuring all characteristics mentioned before are:
Is an objective and quantitative process to monitor / audit bunds compliance to standard in real time.
Cost and time efficient solution as to comply with inspectorate recommendations then survey would be required, incurring in extra cost to audit.
Visibility across all active bunds and ranking of deficient sections to prioritise as per criticality.
Next is presented an schematic of the sensors installed on a truck and scanning the bunds at both sides.
Goonawardene/Crosby – Use of Laser Scanners in an Underground Coal Mine for Strata Monitoring, Drift Convergence & Incident Investigations
Geology and Geotechnical Superintendent, Anglo American – Grosvenor Mine
Surveying Superintendent, Anglo American – Grosvenor Mine
The risk of fatalities due to roof and rib failures is still prevalent in underground coal mines which highlights the fundamental importance of monitoring roof and ribs in underground roadways. Monitoring strata deformation and convergence in underground roadways is a key metric for measuring instability of excavations. Visual inspections, telltales, extensometers and instrumented bolts are some of the methods used to quantify strata deformation.
The significant limitations of the current methods only provide a point-measurement along the roadway. Using laser technology allows the mine to scan and measure large regions of roof and ribs across continuous regions with millimetre accuracy.
The Maptek SR3 laser scanner has been used as a control during the rib optimisation trial at Grosvenor. This technology provides a baseline scan and subsequent scans to ascertain the extent of deformation throughout the active development mining areas. Thus, allowing geotechnical engineers to assess the adequacy of the trialled support system. Moreover, this technology allows geotechnical engineers to better analyse geological anomalies (fault orientations, dips, throw), bolting tolerances and excavation dimensions in an effective manner.
Goonawardene/Elliot – Proactive Floor Fracturing Using UIS Drilling
Geology and Geotechnical Superintendent, Anglo American – Grosvenor Mine
Trainee ERZ Controller, Anglo American – Grosvenor Mine
A series of floor heave and gas inrush events have occurred during the development mining process in MG103 and MG104 at Grosvenor Underground Coal Mine. These events have exposed coal mine workers to elevated levels of methane preventing safe mining operations.
The presence of an undrained source of gas in the immediate floor, geotechnical floor characteristics, loading environment and various other factors have contributed to the dynamic floor failure. Methane released during these events are originating from the underlaying thin Goonyella Middle Lower (GML) seam which is a thin carbonaceous layer with high ash content. The 1m – 5m interburden thickness between the GM seam and the GML has an increased likelihood of the floor gas release events.
Based on the analysis of these gas events, creating a conduit in the interburden between the GM seam and GML will allow the gas to freely release to the development roadway during development drivage. This will prevent the build up of gas within the interburden creating a floor gas release event.
The proactive interburden fracturing was initiated using water pressure generated from a longwall salvage pump. The current UIS drilling equipment was retrofitted with a series of subs, packers and a fracturing tool to initiate a hydro fracture within the drilled UIS borehole. Once the packers are fully inflated and in position, a diversion valve is then activated to allow the fracturing tool to inject high water pressure to the desired location. Thus, given the complexity of predicting verticality of the hydro fracture in the interburden, a UIS borehole was drilled in the lower section of the GM seam as proving hole to check the effectiveness of hydro fracture.
The main benefit of the proactive interburden fracturing process is having the ability to reduce the likelihood of exposing development coal mine workers at the face to high methane levels.
Operations Manager – Mine Inertisation, Queensland Mines Rescue Service
Due to the mining environments in some underground operations, particularly longwalls, where the void space in the goaf becomes wider and longer, the potential for spontaneous combustion and fire events is possible and, in some cases, has happened.
The nitrogen foam table is relatively quick to deploy, set up and become operational delivering the gas mixture to the required area. The water in-foam cools the heating whilst the nitrogen gas displaces the oxygen.
Using the nitrogen foam table supplies a medium of water foam and nitrogen gas. The water in-foam cools the heating – one leg of the fire triangle whilst the nitrogen gas displaces the oxygen – second leg of the fire triangle.
The nitrogen foam table allows for the distribution of the gas/foam mixture to either one borehole or by opening secondary valving, an additional borehole can be treated at the same time. Where a spontaneous combustion/fire event has been identified mid pillar, the utilisation of the table to treat two boreholes at the same time will greatly assist in the reduction or elimination of that event.
When drilling boreholes from the surface into underground voids the nitrogen foam table allows the gas/foam mixture to be utilised to create an inert shield whereby the foam acts as a wetting agent to prevent any incendive sparking during the drilling process & the gas displaces any potential oxygen present.
In mining areas: Such as the maingates of longwalls where there is oxygen contained within the airwash zone the gas foam mixture could be utilised to create a “plug” behind the maingate face end shields which would reduce / eliminate any airwash issues. The table can be readily located adjacent to a seal site either prior to or after the seal installation. The gas/foam mixture can be distributed from the nitrogen foam table via piping through the erected seal or hosing through the proposed seal site.
Howell/Pendrigh – Water Treatment Plant Inlet Screen Blower
Tailings and Water Coordinator, Rio Tinto Weipa Operations
Tailings and Water Electrician, Rio Tinto Weipa Operations
During normal operation at the Water Treatment Plant the inlet screen in the Bio Reactor blocks with debris, sludge and fecal matter. The cleaning of the inlet screen was a laborious task that exposed maintainers to raw sewage and repeated manual handling risks. The crew came up with an engineering control that completely prevented the inlet screen from blocking, eliminating the need to remove and clean the screen. With this new system functioning the crew have removed a great deal of frustration and reduced the handling of this inlet screen to planned maintenance intervals and significantly reducing the crew’s exposure to the biological risk.
In continuing with the desire from industry to share in key learnings from site-related incidents and following on from the themes of previous conferences, this session will be an open forum from people (within the industry) who will be talking about key issues and challenges faced at times on their site.
This session will be a grass roots session without “spin”. A simple presentation outlining what occurred and what changes have been implemented to ensure that things are being done differently. It is for you to consider the relevance to your site and determine if you have a similar exposure, and the controls in place to reasonably preclude a similar event.
Facilitator: Damien Wynn, General Manager and Senior Site Executive, AngloAmerican - Grasstree Mine
SharingtheirExperiences:GraderFatality Incident and Tree Felling MultipleInjury Incident
Paul Stephan, General Manager and SSE, Anglo American Moranbah North Mine
North Goonyella Spontaneous Combustion Event
Peter Baker, Senior Vice President, Underground Operations, Peabody Australia
DrillRigIncident at Bulgar Open Cut, New South Wales
Jeff Kelly, Operations Manager, Glencore
Lansdowne – Blind Intersection Warning LED Indication
Outbye Electrical Coordinator
A recent incident report identified a “Near Miss” at an underpass intersection between the 2nd main travel routes of the mine, involving a loader and a man transporter. Safety meetings with crews identified that with the LED strip lighting underground, it made it difficult to identify vehicles entering the main headings from blind corners, and suggestions were made to remove strip lighting from around the underpass intersections to allow identification of vehicles at the intersection (via headlights on the vehicles).
After further consultation, it was decided not to remove the current lighting from the intersection but to find a solution that would work within all the current controls under the Mine Transport Rules. Work was already being trialled on using coloured LED indication for belt monitoring purposes, and testing began on using the same string of LED to use an amber light to give an indication of movement from around the blind corner. An ultrasonic system was chosen, as a way of removing human behaviour, and testing to confirm functionality, so that either vehicle or pedestrian would activate the warning lights. A trial was put in place at 30ct underpass to test overall functionality and allow feedback from the workforce as to what changes were required prior to implementing through out the mine.
By adding an autonomous warning system, it gives a visual warning to vehicles/pedestrians in the travel roads of movement around the blind corner. Being autonomous, there is no reliance on people’s behaviours or attitude.
Already looking at using the same system to change existing block lights on site to ultrasonic, replacing existing drift lighting with the same LED strips, use of LED strips to indicate gas levels at TG machine doors.
Combined current technologies to achieve working system.
Approximate Cost – $2600 for single control box and lighting
Overburden Supervisor, BMA Saraji Mine
Tragically Saraji Mine had a fatality on New Year’s Eve 2018 involving a bulldozer rolling down an embankment. The first responders to this incident required the use of heavy duty slings and shackles to upright the dozer. This involved personnel traversing down a steep embankment on undulated ground during the night carrying D-shackles that weighed approximately 62kg each, this created a significant manual handling risks to the people involved.
Post incident, Saraji became aware of light weight synthetic couplings that are made specifically for the marine industry that significantly reduced the weight whilst providing exceptional strength properties.
We reached out to the manufacture of the light weight synthetic couplings in New Zealand in an attempt to replicate this technology within the mining industry. By substituting the existing steel D-shackle with a custom made light weight synthetic design, we have reduced the potential of a manual handling incident when recovering surface mobile equipment or the potential for stored energy within the steel to become airborne should the steel D-shackle capacity be exceeded.
The soft couplings were tested to 175,000 kg for a maximum breaking force (MBF) of 510,000 kg without breakage and have a total weight of 8.2 kg compared to the 62 kg steel D-shackles that are normally used.
The synthetic couplings have been successfully trialled on site to extract various pieces of surface mobile equipment. They have been included as mandatory items in the emergency equipment recovery trailer along with other items to aid in the immediate recovery should the need arise.
Owens/Zanette – Broadmeadow Proximity Detection System
Project Manager, BMA Engineering
Project Supervisor, BMA Engineering
The Broadmeadow Proximity Detection (PDS) Project was initiated to address the risk of vehicle to pedestrian and vehicle to vehicle interactions in a low visibility environment. There have been numerous deaths and injuries which have occurred due to workers being contacted or crushed by mobile equipment in the underground environment. Following the fatality at the Moranbah North Coal Mine (2007), a Shuttle car incident at San Juan and the fatality at Escondida in 2016. Broadmeadow is committed to the implementation of an engineering solution. Proximity Detection Systems have the potential to reduce the risk of underground mobile equipment injuries and fatalities.
The project has completed stage 1 trials of a Proximity Detection System (PDS) fitted to vehicles (Shuttle Car (SC), Loader (LHD) and Personnel Transporter (PJB)) designed to detect the presence of a pedestrian or vehicle in a hazardous location around a machine. Should a worker enter this zone, the system will issue a warning signal – a combination of audible and visual alarms – to notify the individual as well as the machine operator of potential danger. The system was also configured on the SC to automatically slow and stop when a pedestrian was detected in the warning and danger zones of the machine. Stage 1 of the trial was conducted both in surface and underground testing areas in isolation from production activities.
The PDS is currently in stage 2 trials at Broadmeadow. During this stage the PDS (with auto slow\stop enabled) has been installed on an operating shuttle car currently in production underground in a Broadmeadow Development panel. This is the first SC in Australia to run in production with a PDS in full auto slow\stop mode.
A LHD fitted with audible and visual alarms is also being trialled underground in a production environment, this trial involve fitting various attachments to the LHD including personnel-baskets, pipe trailer and stone dust pod. Various attachments require configuration changes to the system to ensure the machine zone sizes can grow and shrink dynamically to suit the attached implement or machine speed. One of the most challenging parts of the PDS trials is the application of silent zone technology which enables an operator(s) to work within the fields of the machine in what is designated as a safe area i.e. cab or inside a personnel-basket. This silent zone technology has been applied to a bolter\miner and at Broadmeadow and it effectively makes all operators standing in safe zones on the bolter\miner platform invisible to the shuttle car PDS as it docks to the machine for loading.
During the course of the trials over 200 different vehicle to pedestrian and vehicle to vehicle scenarios have been tested. If a pedestrian comes within 7 to 8 metres of a shuttle car it will slow to 50% speed and if a pedestrian comes within 4 to 5 metres of the shuttle car it will automatically stop before hitting the pedestrian. Feedback from operators has been that the system gives them a greater awareness of machine NO-GO Zones and operators are standing further back from the machine.
The PDS is current installed on the following machines at Broadmeadow:
Full Auto-Stop Mode – 2 x Shuttle Cars (with a 3rd installation in progress)
Warning only Mode – 1 x Underground Personnel Transporter, 2 x Underground Loaders (LHDs), 1 x Electric Vehicle, 1 x Moxy Articulated Truck