UNEXUP is a direct continuation of the UNEXMIN project.
In UNEXMIN efforts were made towards the design, development and testing of
a robotic exploration technology for underground flooded mines, with
navigational and geoscientific instruments. In UNEXUP the main goal is to
raise commercial interest and improve the system's hardware, software and
capabilities. The UX-1 NEO, to be developed and tested in 2020, will address
the limitations detected during UNEXMIN field missions, and will meet the
needs and requirements from mining companies, geological surveys and other
potential customers. In addition, a new robot will be built and added to the
system, to be ready in 2021, which will open further mineral exploration
possibilities.
Introduction
UNEXUP (2020, http://www.unexup.eu, last access: 17 July 2020, project number 19160)
is an international project co-funded by EIT RawMaterials. The project will
improve and test an existing robot-based exploration technology to re-survey
Europe's underground flooded mines by environmentally friendly methods and
bring the semiautonomous exploration of flooded mines to the market.
Background
The predecessor project – UNEXMIN (2020, http://www.unexmin.eu/, last access: 17 July 2020)
– was among the “Horizon 2020 Technology Success Stories” in the Raw
Materials Week 2019 (European Commission, 2019a), because the novel UX-1 robotic system
offers one potential solution to address raw materials supply in Europe. The
EU depends on the import of mineral raw materials (European Commission, 2019b), despite there
being a considerable number of closed mine sites in Europe (Didier et al.,
2008), some of which still contain valuable mineral resources that were not
exploited due to different economic or technological constraints in the
past. One such example is the South Crofty tin mine in the UK (Mining
Journal, 2019). Most of these abandoned sites are now flooded and hard to
re-explore without costly dewatering. In addition, there is a lack of
information about historical mines, where documentation was lost or not made
at all. Based on this background, UX-1 robotic prototypes (Fig. 1) were
developed within UNEXMIN, which can gather high-quality geological,
mineralogical and topological information from currently inaccessible mine
sites. These capabilities have been tested in five field trials, such as the
abandoned Idrija Mine in Slovenia (Pučko et al., 2018) and Ecton Mine
in the UK (Pučko et al., 2019), which proved the system's operability.
Part of the UNEXMIN project was also to develop an Inventory of Flooded
Mines in Europe, which currently contains more than 11 000 flooded mines
catalogued: http://unexmin.geologicalsurvey.be/ (last access: 17 July 2020, UNEXMIN Inventory of Flooded Mines, 2020).
UX-1 robot (figures from UNEXMIN GeoRobotics Ltd., 2020).
Objectives and approach
UNEXUP aims to commercially deploy a new exploration and mine mapping
service based on the UNEXMIN technology. The service intends to address the
needs and requirements from mining companies, geological surveys and other
stakeholders that can benefit from a semiautonomous underwater geoscientific
surveying campaign.
Technology developers will improve the hardware, software and capabilities
of the current UX-1 robotic platform that was developed within the UNEXMIN
project. This upscaling vehicle will address the limitations detected during
UNEXMIN field missions, and the added functions will also cover the input
and requests from potential customers. The improved version of UX-1 (UX-1
NEO) will be developed and tested in the field in 2020.
Moreover, an additional robot will be added to the UX series – UX-2. It
will be able to conduct even more challenging surveying missions in flooded
environments, extending the current exploration capabilities of the UNEXUP
technology.
Main objectives of the UNEXUP project are: (1) Improve the current UX-1
system's hardware and software; (2) Build an additional, more complex robot,
with further capabilities and sensors; (3) Test the robots' performance in
different pilot sites; (4) Bring commercial interest to the innovative
technology and launch the service into the market.
Materials and methods
The current UX-1 robots, developed in UNEXMIN, are equipped with the
instruments presented in Table 1, including different sensors and
instruments needed for semiautonomous navigation. These robots were then
launched in real mine environments, in order to test robot's navigation and
movement systems, autonomy and geoscientific sensors, and then to use the
obtained data for improvement of data post-processing protocols.
UX-1 characteristics and instrumentation.
Overall characteristics of UX-1Navigational InstrumentsGeoscientific Instruments
Maximum operation depth: 500 m
Spherical shape
Diameter: 0.6 m
Approx. weight: 112 kg
Power consumption: 250–400 W
Maximum speed: 1–2 kmh-1
Neutral buoyancy
Multibeam sonar
Scanning sonar
Digital cameras (five)
Doppler velocity sensor (DVL)
Inertial measurement unit (IMU)
Structured light system (SLS)
Scanner and lasers
Propulsion and ballast systems and pendulum
pH and EC units
Temperature and pressure sensors
Water sampler
Magnetic field units
Gamma-ray counter
Sub-bottom profiler
Multispectral camera
UV fluorescence camera
The UX-1 robot and its sensors were tested in 5 different real flooded mine
environments (pilots) between 2018 and 2019. The pilots were selected in
order to start with simpler mine layout with easy accessibility, and then
proceed with more and more challenging environment during pilots:
Kaatiala Mine, Finland (June 2018).
The Kaatiala is an open-pit, flooded pegmatite mine with some underground
workings at the bottom. In this mission UX-1 was successfully tested in two
test areas: shallow part, and deep part of the quarry with the underground
tunnels, where depth control, navigational and ballast systems were tested.
The dives lasted 2 h approximately, reaching a maximum depth of 30 m
(Žibret et al., 2018). The main objective of the mission was to test the
robot's propulsion, navigation and instrumentation systems (Henley et al.,
2019).
Idrija Mine, Slovenia (September 2018).
The Idrija Mine is a mercury mine, considered as one of the UNESCO World
Heritage sites. A total of 11 dives were done to test the movement, control
and 3D mapping capabilities in confined environments. UX-1 proved to work
well under challenging environments – limited visibility, narrow passages
and limited airflow (at the launching point) – with the first fully
autonomous dive up to a depth of 2 m. The robot reached the bottom of the
shaft at 26.2 m and mapped the entire area in approximately 2 h: 1.5 h
descent and 0.5 h return. The pendulum system was tested with dives at
different pitches (0 to 90∘), and the multispectral
camera unit has proved to be working well (Pučko et al., 2018).
Urgeiriça Mine, Portugal (March/April 2019).
Urgeiriça Mine is a closed underground uranium mine hosted by a granite
pegmatite. The robotic platform accomplished a total of 18 dives in this
mission, with a maximum depth reached at 106.5 m. There are 6 vertical
shafts in the mine, and the galleries can be accessed from the main “Santa
Bárbara” shaft (Henley et al., 2019). The mine's main shaft and the
entrance of the side tunnels have been explored and mapped, gathering
valuable data such as video footages, 3D point clouds of the shaft and side
tunnels, multispectral and UV fluorescence lights images of the rock wall
(Žibret et al., 2019).
Ecton Mine, UK (May 2019).
The Ecton mine is a Cu–Zn–Pb mine that was flooded between 1856–1858, and
the flooded parts have never been surveyed before. Two robots were launched
(UX-1a and UX-1b) in a total of 10 dives in three different sites – up to
125 m depth, to navigate and acquire data. The control systems were
successful at maintaining the desired depth during the dive.
Three-dimensional (3D) models were constructed from sonar and Structured
Light System data, showing the size and shape of the mined pipe workings.
High-resolution videos from all five cameras, for LED “white” illumination
and UV fluorescence illumination, were also produced and gave valuable data
on the geology and mine infrastructure archaeology. During the Ecton test,
the robots also successfully collected data from the MSU (multispectral
unit), EC (electrical conductivity), pH meters and sub-bottom profiler.
Water samples were also collected (Pučko et al., 2019). The field
mission at Ecton mine provided a wealth of geological data, where the
complexity of the structures, rock types and mineralization could be
identified by the UX-1 dives (Henley et al., 2019).
Molnár János cave, Hungary (June/July 2019).
The Molnár János cave is a natural underwater thermal cave system
that was particularly selected for autonomy testing. The cave system reaches
up to a length of 7 km, with sections up to 100 m depth, where 10 autonomous
navigation missions were successfully achieved.
All tests were performed without causing harm to humans, equipment or the
environment. The data from these tests were collected and reviewed by
professionals in the field of mining and geology, to evaluate the usefulness
of this technology for potential end-users, and to identify gaps and
bottlenecks that need to be addressed prior to commercialisation. The
findings are presented in a report by Henley et al. (2019), which provided
guidelines for the technology developers of UNEXUP.
Results and discussionResults and geoscientific evaluation of UNEXMIN pilots
During 5 pilots, the UX-1 robot collected almost 9 TB of data during almost
100 h of operations. The specification of pilots is presented in Table 2.
Five pilots in numbers. Two different robots (UX-1a and UX-1b with
slightly different instruments were tested).
Post-processed data from the Molnár János cave – Budapest,
Hungary (figure from UNEXMIN GeoRobotics Ltd.).
Examples of geological structures, which were detected by UX-1
visible light cameras in flooded environments during Ecton Mine pilots
(modified from Žibret, 2019). Sigma 1 (σ1) points the direction
of greatest compressive strength.
An example of geological cross sections, which can be built
according to the robot's data (modified from Žibret, 2019).
UV fluorescence camera enhancing the multiple generations of
calcite veining – Ecton Mine, UK (figures from UNEXMIN GeoRobotics Ltd.).
In this paper, we will present only some of the most relevant results, which
illustrates the UX-1 robot capabilities and are the basis for the
geoscientific evaluation of the technology. The results show that the
current version of the UX-1 series is already capable of conducting
underwater missions and produce useful geoscientific data from flooded
environments, which can potentially add value to exploration campaigns of
mining companies. For example, the geological evaluation of the UX-1
technology, which is available today, can be described as follows
(Žibret, 2019):
The robotic platform can identify underwater openings and tunnels even if
the visibility is near-zero, due to the scanning sonar and structured light
system that can produce point-clouds of the mine (Fig. 2). This
information can support drilling plans, for example.
If the water is clear, the visible light cameras can capture high quality,
real-life images from flooded mine sites, allowing the determination of rock
types, geological and tectonic structures (Fig. 3). Together with
point-clouds, geologists are able to build geological maps and
cross-sections (Fig. 4) if the rocks are exposed. The scanning sonar,
structured light system and the robot's internal positioning data can also
allow the estimation of orientations of geological structures (i.e. dip,
bedding, fault planes, etc.), thus allowing the creation of structural maps.
pH, EC, thermometer and the water sampler can help detect physical and
chemical characteristics of the waters, as well as potential hydrothermal
activities and CO2 degassing on active faults. The possibility to
collect water samples from flooded environments can support dewatering
plans.
The multispectral camera, together with UV fluorescence light and gamma-ray
detector allow UX-1 to detect some minerals (Fig. 5). Automatic
calcite detection has been calibrated with machine learning and tested under
real-life environments. Automatic detection system for other minerals is
possible and will be added during UX-1 upscaling.
The gamma-ray counter (Fig. 6) can help in the identification of minerals
with natural radiation, such as uranium (U) ores or thorium (Th) rich rocks.
An example of the results obtained by the gamma-ray sensor. The
robots' internal navigation system also records their location and
orientation, so 3D radiation maps can be produced in the future. Data were
collected during a dive in Urgeiriça uranium mine, Portugal (Žibret,
2019).
Input and feedback from the mining industry during UNEXMIN dissemination and
outreach activities allowed the consortium to understand the market needs
and requirements for the robots. Based on that, one of the main goals of
UNEXUP is to build an upscaled version of UX-1 (Table 1), which will address
the limitations found during the field trials conducted within UNEXMIN. The
limitations that will be addressed include: motion limitations (limited
lateral motion and no active pitch stabilization), limited modularity,
ballast system affects the centre of mass, heavyweight that makes it
impractical to transport in abandoned mines (112 kg), battery replacement
and data retrieval is time-consuming, and other detected problems with less
relevance (thermal dissipation should be improved, not easy to unplug
optical fibre, limited energy management, some water ingress issues).
Future plans
The UX-1 robotic platform, developed within the UNEXMIN project, was
successful at raising interest from the geoscientific community in Europe.
Additionally, it demonstrated that the current instrumentation and sensors
are already capable to produce valuable mineralogical, geological, and
topographic information from underwater environments. However, the pilot
missions and lab tests performed during the project exposed some
malfunctions and limitations in the current robot.
Therefore, the purpose of UNEXUP is to take advantage of the lessons learned
from UNEXMIN, to build and commercialize the upscaling version of UX-1: the
UX-1 NEO. While sharing similar dimensions and functionalities, the new
robot will be equipped with improved software and hardware, in order to
increase its array of capabilities and address the issues detected in the
“old” UX-1.
Besides, the project also will develop the UX-2 in the near future, to be
part of the UNEXUP robotic platform. The UX-2 will be capable of reaching
greater depths, of up to 1500 m, for missions in deeper environments.
In addition, the robot will have increased capabilities and scientific
payload, which have not been fully defined yet (September 2020).
UX-1 NEO
The upscaling version of the UX-1 robot, which will be ready in the second
part of 2020, will be equipped with improved hardware and software that are
expected to meet the users' needs. The UX-1 NEO can be characterized by the
following improvements (Table 3).
Hardware and software improvements of UX-1 NEO.
HardwareSoftware
Modular design
Lower weight
Full 6 DOF thruster control
High Density Polyethylene frame
Flotation foam
6 Cameras with new design and embedded processing: Front, back, left, right, top and bottom.
6 SLS units, SLS system miniaturization
Pressure tolerant pendulum, vessels and batteries
Removable disk enclosure
Water/pressure proof instrumentation modules
Geoscientific instruments
Reduced number of operating personnel
Reduced mission setup time and requirements
Improved data collecting and processing efficiency
UX-2
The second robot to be added to the platform will be built in 2021 and
improved in 2022. UX-2 will be developed to address more challenging
surveying missions, with increased modularity, higher TRL and higher
operational depth (∼1500 m). For the production of
geoscientific data – not fully defined yet (September 2020), a number of
instruments are expected: (1) Hyperspectral unit, (2) Rock sampler (supported
by a robotic arm), (3) Water sampler, (4) Water chemistry measures, and (5) Fluxgate magnetometer. The modularity of both UX-1 NEO and UX-2 will allow
the robots to share some of these geoscientific instruments, however, the
rock sampling unit is envisaged to be exclusive of UX-2.
UNEXUP field trials
Field trials will test the capabilities of the UX robots under real-life
industrial conditions, while demonstrating the UNEXUP technology efficiency
under the most challenging requirements and needs of the mining community.
The objective of the pilots is to implement a real “service-to-client”
approach, including customer relations, contracting procedures, pilot
implementation and the production of final outcomes and studies. Each
mission will be planned to start with an orientation workshop and will end
with an on-site evaluation workshop, working together with qualified
representatives of the client.
The selection of the test sites will be done following four priorities: (1) geoscientific interest and business promotion; (2) client's willingness to
pay for the service – partial to full payment in light of the maturity of
the technological solution; (3) risk, as more challenging missions will be
conducted towards the end of the project; and (4) possibility to diversify
the service, e.g., to extend the client database. After each mission, the
gathered data will be post-processed using specialized software, which will
enable the 3D visualization of the mine using virtual reality.
Expected future results
By the end of the project, the UNEXUP robot-based technology is expected to
require less maintenance and smaller crew (from 4–5 to 2–3 people) during
the missions, and also to address the limitations of the previous UX-1
robot. In addition, improvements on processing software will enable the
visualization of geological features in with fewer false points and echoes.
Based on the Research Roadmap developed within UNEXMIN (Lopes, 2019),
targeted technological improvements are:
Robotics and mechatronics: Hull that can withstand greater depths
(titanium); further miniaturisation of subsystems; reliability and
survivability analysis.
Mapping and sensors: Improve real-time navigation and mapping; add
environment feature usage in the navigation and localization; develop user
friendly robot tools; improve the ground support systems.
Autonomy, guidance and control: Robust position estimation; full on-board
computing and testing; autonomous exploration methods, safety procedures and
recovery actions; extensive tests of navigation software in relevant
environment; tetherless control tests in relevant environment for autonomy
validation and performance evaluation.
Scientific instrumentation: Improve scientific instrumentation – water
sampler, FGM (fluxgate magnetometer) unit, gamma-ray counter, sub-bottom
profiler; and create new tools – like a rock sampling unit.
Postprocessing: User-friendly interfaces to allow direct use of video and
virtual-reality software by non-programmer geologists; development of
surface modelling and intelligent filtering of point clouds to allow
superimposition of camera images into 3D models; improving the efficiency of
the structural analyses from 3D point clouds.
Robotic platform: Modular version of UX-1; improve energy management system;
increase depth range (1500 m).
Commercial exploitation
The technology developed in UNEXMIN and to be enhanced in UNEXUP, as
described above, will be used in providing commercial services by UNEXMIN
GeoRobotics Ltd. (UGR), a company founded and owned by a number of the
UNEXMIN/UNEXUP consortium participants. UGR will offer a range of services
for surveying and exploration of flooded underground mines in Europe and
beyond. These services will include training and preliminary site
assessments using not only its own UX-1 NEO and UX-2 submersible robots but
also, where appropriate, industry-standard remotely operated vehicles (ROVs)
from manufacturers such as Blue Robotics and Deeptrekker. This will allow a
combination of flexibility to provide appropriate levels of technology for
each task while giving some protection to the advanced UNEXUP technology in
new and unknown environments. The relatively inexpensive ROVs will act as
the “canary in the mine” to warn of potential hazards, and also as training
platforms for new operators. The UX-1 NEO and UX-2 will be used for detailed
studies, especially those that involve deep dives within complex and
undocumented mine geometries.
Conclusion
The climate change goals in Europe will require a substantial increase in
mining activities, since the technology involved in solar panels, wind
turbines and electric cars require great amounts of rare-earth elements and
other metallic raw materials (e.g. lithium, cobalt and others) (European Commission, 2020).
To guarantee a constant supply of critical raw materials to the EU, there is
a need to re-think how the mining industry will address these issues.
UNEXUP will offer the necessary tools to re-survey flooded mines in a
sustainable and economically feasible way. It will be an environmentally
friendly method to discover new mineral resources in abandoned flooded
mines, and will allow the mapping of geological structures, development of
cross-sections of the sites, identification of economically interesting
minerals, and obtaining exploration data without costly dewatering. These
data will be gathered and post-processed without human risks or major costs
and will provide tools for smart and accurate decision-making regarding
drilling plans and dewatering investments in mines that are found to be
promising for future exploration.
The development of additional instrumentation (geoscientific and
navigational) to the new UX series will be justified by market requirements.
Therefore, the UNEXUP multi-robotic platform will be built and adapted to
perform commercial underwater surveying missions, which differs from the
“pure scientific interest” that was targeted within UNEXMIN lifetime.
Mining companies, geological surveys or any other industries that can
benefit from the technology are encouraged to contact the project
representatives, to discuss the possibility of conducting field trials in
their own sites for a reduced price. These pilots will increase
geoscientific and spatial knowledge about these sites and will help the
UNEXUP team to detect any limitations or malfunctions in the robots'
performance. This will provide guidelines to the UNEXUP technology
developers to properly calibrate and adjust the software and hardware of the
future UX robots, to improve their performance and turn them into an even
more reliable technology to explore underground flooded mines. The
successful completion of the lab tests and field missions will be the main
commercial showcase for the UNEXUP technology.
In addition to the benefits that the UNEXUP technology can provide regarding
raw materials supply in the EU, the possibility of re-opening abandoned
mines will foster the economy by creating jobs – both direct and indirect
– at regional, national and supra-national levels in Europe.
Data availability
Authors use information from both public sources, as mentioned in the text,
and private ones, such as is the Grant Agreement signed between the UNEXUP
consortium and EIT RawMaterials, which is not publicly available.
Author contributions
All authors provided their contribution to the development and review of
this paper.
Competing interests
The authors declare that they have no conflict of interest.
Disclaimer
The paper expresses only the authors view and funder is not liable for any
information contained within.
Special issue statement
This article is part of the special issue “European Geosciences Union General Assembly 2020, EGU Division Energy, Resources & Environment (ERE)”. It is a result of the EGU General Assembly 2020, 4–8 May 2020.
Acknowledgements
Special thanks to the UNEXMIN and UNEXUP
consortium participants, which are, together, contributing to the
development of the project.
Financial support
This project is supported by EIT RawMaterials (project no. 19160).
Review statement
This paper was edited by Antonio Pio Rinaldi and reviewed by Juan Alcalde and one anonymous referee.
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