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Τετάρτη, 23 Αυγούστου 2017

Application of Drones for Mining Operations

Small drones can help many firms find cheaper and safer ways to map deposit sites, explore for minerals, and calculate inventory via remote control. 
by Alex Vyazmensky, Ph.D.

1. Rise of the Drones.
Civilian Unmanned Aerial Vehicles (UAVs) or Drones are versatile flying machines, which can perform a variety of tasks, including, but not limited to, surveying and mapping, inspections, small cargo delivery, aerial photography and video surveillance. Drones are quick to deploy, they can be launched, flown and landed by an operator, their functionality can also be fully automated. Over the last few years use of drones is growing exponentially. Drone based services are becoming increasingly important in construction, agriculture, insurance, media and entertainment, and other industries. A recent PwC study estimates the potential value of the mining industry services that, in very near future, can be replaced by drone powered solutions at $4 billion dollars (Link 1).

2. Drone Platforms and Data Acquisition Technology.
There is a wide selection of commercially available drone platforms variable in shape, size and technical characteristics, they can be broadly divided into rotary and fixed wing types. Popular lightweight rotary drones are compared in Link 2.
For surface applications GPS allows accurate drone positioning, while in underground applications SLAM (Simultaneous Localization And Mapping – Link 3) algorithm enables Drones can be equipped with photo and video cameras, laser scanners, gas sniffers, hyperspectral, infrared, thermal and many other sensors. Major drone solution providers offer machines pre-equipped with task specific sensors and software packages to operate the drones and interpret the acquired data (few examples – Link 4, Link 5, Link 6 and Link 7).

Drones are particularly suitable for airborne video surveillance and spatial data acquisition. The 3D spatial data can be extracted from a series of digital photos taken by a drone utilizng a photogrammetry technique or generated by LiDAR (Light Detection and Ranging) laser scanning surveys. Link 8 provides an introduction into drones based photogrammetry and LiDAR mapping, while Link 9 compares these techniques for outdoor applications. It should be noted that HD videos recorded by drones can be converted into georeferenced 3D models, as illustrated in Link 10, such models however are not as accurate as photogrammetry or LiDAR. A recent introduction of 360° video cameras offers a new and promising avenue in geospatial data acquisition - Link 11.

3. Mining Applications.
A list of principal applications of drones in mining operations, taking into consideration capabilities of drone and data acquisition solutions currently available, is provided below:
Operational surveillance for short term mine planning, surveys for production blast reconciliation and blast performance assessment pit surveys for mine planning, geological and geotechnical mapping, stability and hydro-geological conditions monitoring remote inspections, surveys and mapping of difficult to reach pit sectors/benches, underground development closed for access, voids (stopes, potentially caves), shafts, ventilation raises and ore-passes underground development surveys for mine planning and stability monitoring underground ventilation surveys: air quality / velocity / temperature stock pile volume assessment mine lease area environmental inspections remote surveys and inspections of tailings dams remote inspections of mine machinery and infrastructure to identify maintenance needs, video surveillance for search and rescue operations, and incident investigations.

Five valuable lessons learned about drones in mining

4. Some Advantages and Limitations of Using Drones.
Among the key advantages of using drone based solutions are:
1.Remote access allows safer execution of survey and inspection tasks, and leads to fewer interruptions of critical mining activities
2.Quick access to the area of interest, particularly for surface applications, allows to streamline operational workflows
3.Relatively quick and cost effective digital data capture on as required basis

Some of the issues to be aware of, when considering a drone based solution:
1.Local drone regulations - many countries require permits and/or have strict drone operating rules in place - Link 12
2.Managing a drone - mine equipment - personnel contact requires a thorough preparation (flight paths checks, warning system, risk analysis and etc.)
3.Drones have limited operating range and battery life (depends on model), these constraints should be carefully considered against planned application.
4.Drone machinery and data acquisition technology is developing very fast, more capable and sophisticated solutions become available every few months, thus leasing drone solutions or hiring a drone services provider may be a preferred option
5.Drones are quite fragile, damaging or crashing a drone can be costly

It is worth noting that choice of the drone solution should always be site specific, ideally a drone should serve several purposes.

5. A Look into the Future.
Drone platforms and sensors are getting smaller, lighter and less expensive; this will open possibilities for new drone applications.In a foreseeable future, drones are likely to become an integral part of the mining “Internet of Things” framework (Link 13 and Link 14), acting as auxiliary data collection, communication and delivery devices for autonomous mining systems. Drone technology is expected to make a major impact in the mining industry in terms of productivity and efficiency. This however is some years away. As of now, drones potential to add value to the mining operations remains to be fully explored!

Additional Resources:
Article - Case study - Drone Mapping of a Coal Mine in Canada
Presentation - Case study - Application of Drones at St.Ive's mine (Australia)
Video - Drone flyover of a large open pit - Chino mine (USA)
Video - Autonomous drone trials in a German coal mine (note auto mapping function)
Video - Drone inspection of UG development and an open stope at Fosterville Gold Mine (Australia)

[Επιμέλεια: Πέτρος Τζεφέρης]