The 12 M€ research project X-Mine is coordinated by VTT Technical Research Centre of Finland and funded by the European commission Horizon 2020 programme. The X-MINE project studies and develops X-ray and 3D vision based sensing technologies and 3D ore deposit modelling. The sensing technologies have been integrated in two types of large-scale prototypes: drill core analysers and mineral sorting prototypes, which are being demonstrated at the four mining sites of the project in Sweden, Greece, Bulgaria and Cyprus. The sites have been chosen to illustrate different sizes (from small-scale to large-scale) and different target minerals (zinc-lead-silver-gold, copper-gold, gold). The targeted impacts of the X-Mine project include a 20 % reduction in transportation costs through more efficient ore and waste separation, a 7 % reduction in waste rock, and a 10 – 30 % reduction in energy consumption and CO2 emissions. Preliminary results show that these numbers could be achieved, and the project is continuing research to quantify the impacts more precisely.
ABSTRACT
The X-MINE project supports better resource characterisation and estimation as well as more efficient ore extraction in existing mine operations, making the mining of smaller and complex deposits economically feasible and increasing potential European mineral resources (specifically in the context of critical raw materials) without generating adverse environmental impact.
The project will implement large-scale demonstrators of novel sensing technologies improving the efficiency and sustainability of mining operations based on X-Ray Fluorescence (XRF), X-Ray Transmission (XRT) technologies, 3D vision and their integration with mineral sorting equipment and mine planning software systems.
The project will deploy these technologies in 4 existing mining operations in Sweden, Greece, Bulgaria and Cyprus. The sites have been chosen to illustrate different sizes (from small-scale to large-scale) and different target minerals (zinc-lead-silver-gold, copper-gold, gold) including the presence of associated critical metals such as indium, gallium, germanium, platinum group metals and rare earth elements. The pilots will be evaluated in the context of scientific, technical, socio-economic, lifecycle, health and safety performances.
The sensing technologies developed in the project will improve exploration and extraction efficiency, resulting in less blasting required for mining. The technologies will also enable more efficient and automated mineral-selectivity at extraction stage, improving ore pre-concentration options and resulting in lower use of energy, water, chemicals and men hours (i.e. worker exposure) during downstream processing.
OBJECTIVES
SMART EXPLORATION
3D geological modelling of ore deposits has become an important tool for improved exploration and mine planning. Advanced geological and geophysical methods are applied and integrated to model and delineate the ore body form and extension, as well as any proximal mineralising structures. Geophysical tools typically use a combination of methods (electromagnetic, gravity, magnetic and seismic) adapted to the needs of the local geological environment. The project proposes to integrate X-Ray sensing methods (which are not influenced by the local geological environment) with 3D ore deposit modelling software, in order to add compositional characteristics to the structural ones. The well-defined and accurately delineated structures of the ore deposit demonstrators will make the basis for the “fit-to-purpose” real-time sensing devices to be applied.
SELECTIVE DRILLING
Real-time online data collection while drilling can allow mining companies to make better informed decisions about extending, re-prioritising or diminishing drill holes in order to maximize the efficiency of the mining operations. When exploring for precious metals, one of the most widely used techniques is to identify and monitor geochemical pathfinder elements (such as arsenic or tellurium for gold mining) which require high performance sensing capability. The project will demonstrate novel sensing tools that can support drill core scanning, measurement/analysis while drilling. Improved resource definition can reduce the blasting of excess waste rock (i.e. less release of NO2 and other potential harmful substances) therefore reducing the overall environmental impact of the mining operations.
OPTIMAL EXTRACTION
Mining elements that appear in low concentrations can benefit from fast and accurate analysis. The project will demonstrate how novel sensing technologies can be used to reject unmineralized wall-rocks and gangue minerals at coarse particle sizes, thus reducing energy consumption by excluding redundant materials before transportation, crushing and grinding. Mines are very large energy consumers (to illustrate this fact, think that LKAB alone is responsible for 1.5% of Sweden’s electricity consumption at country level). In practice, the sooner waste rocks and gangue minerals are separated from further processing, the greater the benefit for an efficient and sustainable mining operation, as less energy, less chemicals and less water will be required for downstream mineral processing. The detection and extraction of valuable secondary minerals previously not considered may also reduce the total amount of waste rock, add mineral and metal value, and increase the profitability of the mines, enabling a closed down mine to be reopened, or a hardly profitable mine to have greater operational margins and long term stability.
LARGE-SCALE DEMONSTRATION OF NEW SENSING METHODS FOR MINING
X-Mine project will evaluate and assess the benefits of the new sensing (X-ray, 3D-imaging) technologies in 4 geographically and geologically different mining operations (Table ) with regards to ore structure model, drilling selectivity, extraction optimisation and efficiency, environmental impact, health & safety. The pilot reports will include full lifecycle analysis, socio-economic impact, business planning and health & safety analysis.
| Site | Description |
|---|---|
| Lovisa Gruvan (Sweden) | Lovisa is a small Swedish mine in the area of Lindesberg (Örebro county) producing about 40,000 tonnes of high grade zinc-lead-silver ore annually. Because of the narrow ore zone, a lot of waste rock is introduced in the mining and it is of great interest for Lovisagruvan to find a method that can reduce waste rock, reduce cost of mining, transportation and environmental impact from handling excess waste rock. The mine is also located in the vicinity of the rare earth element (REE) belt located in the western central part of the Bergslagen ore province where ore mineral assemblages found include various combinations of REE-silicates and REE-fluorocarbonates which will also be targeted in the pilot. |
| Hellas Gold (Greece) | The Kassandra mining field, located in the Halkidiki Peninsula in northern Greece, hosts two manto-type stratabound replacement massive polymetallic to base metal sulphide ore deposits in the north and porphyry copper-gold deposits in the south. Hellas Gold operates an underground mine using a multi-stage flotation process to extract a lead-silver concentrate and a zinc concentrate and is expected to process 220,000 tonnes of zinc-lead-silver ore at grades of 6.2% lead, 10.0% zinc and 163 grams per tonne silver in 2016. In parallel, Hellas Gold has a copper ore deposit under development as open pit and underground mining project, part of a major NW trending Tertiary porphyry copper belt, found also in FYROM, Serbia and Romania. |
| Assarel Medet (Bulgaria) | Assarel-Medet is the leading Bulgarian company for open pit mining and processing of copper ores providing around 50% of the national production of copper. The company is the biggest and main factor for the social and economic development and the image of the municipality of Panagyurishte and the district of Pazardzhik. Assarel-Medet processes about 13M tonnes of copper ore per year, thus ensuring sustainable and stable development and production at thorough utilization of the mineral raw materials of the Assarel deposit. |
| Hellenic Copper Mines (Cyprus) | Hellenic Copper Mines exploits the Phoenix and Phoukasa mines, producing over 60,000 tons of high purity (99.999%) copper metal. However, the demonstrator will not focus on the copper ore, but on new activities related to low grade gold-bearing ores in the Skouriotissa area. Gold exploration operations will start in 2017, and within the context of this programme, the demonstrator will seek to validate new technology that could be applied to increase the efficiency of sampling testing of gold ore reserves and possibly, optimize gold recovery during hydrometallurgical beneficiation of low grade gold ore. |
INNOVATIONS
X-Mine project will develop an analytical solution supporting reliable, quick, on-line, real time and forecast data about the ore “in the process” mineral flow, that the operator and the process support systems could optimize critical parts of the process. As a result, the X-MINE project will bring three innovation streams that have the potential to improve the environmental and economic performance of mining operations
ORE DEPOSIT MODELLING
STATE OF THE ART
Various 3D software are currently able to
model the geometry of the ore bodies and
geostatistical information in relation to metal
grades distribution. These tools rely on
geophysical measurement (such as TEM or
TDIP) and drillcore data (such as pXRD and
laboratory bulk geochemistry).
PROJECT INNOVATION
X-MINE will integrate additional structural
geological data from the tomographic rendering of
the drill cores (XRF/XRT scanning) into the 3D
model, providing adequate correlation of persistent
geological markers between drill holes from drill
core logging. X-MINE will support the modelling
of complex ore bodies (in particular alteration
zones) using a folded curvilinear grid in which
specific values from multi-parameter dataset are
embedded in each grid cell. This will result in a
substantially improved resolution of the ore body
obtained at a much higher speed than previously.
SENSOR AND DATA FUSION
STATE OF THE ART
XRF systems are commonly used to deliver
elemental and mineralogical information.
However current XRF systems are only
capable of surface measurements. Penetrative
XRT systems are available for drill core
analysis, but not for in situ applications and
not in combination with XRF sensing,
therefore providing inferior performance for
mineral sorting at high speed.
PROJECT INNOVATION
The project will combine high-energy XRF sensors
(for high accuracy and good penetration), multienergy
XRT sensors (for high penetration, material
sensitivity and throughput) and optical sensors (for
3D characterization). This combination of
technology will enable the system to support both
drillcore analysis and mineral sorting applications,
including high speed processing of low ore grades.
ONLINE ANALYSIS AND SENSOR-BASED SORTING
STATE OF THE ART
Existing sorting equipment suppliers have
proposed solutions based on various
combinations of XRT, XRF, electromagnetic
and optical sensors. Existing systems can
reach a high throughput supporting mining
operations at the expense of a lower limit of
detection (as sensitivity decreases with
higher scanning speeds). These systems are
generally unsuitable to process ore grades
below 0.1% at a rate to slow for production
operation (i.e. integrated with drilling,
blasting and extraction)
PROJECT INNOVATION
The project will provide high sensitivity
instruments (limit of detection <0.1%) that can
provide insight into density and texture, including
grain size and distribution, which is critical to
optimising pre-concentration processes. The
instruments will support a speed of at least 40
tonnes/hour for 10 mm particles with 0.1%
sensitivity. Higher sorting speeds are of course
possible if sensitivity is traded off.