- Strategic Minerals Spain

Since the beginning of Strategic Minerals Europe at the Penouta mine for the revaluation of sterile waste, we have had the collaboration of the research group Resources and Mineral Deposits from the Department of Geology at the University of Salamanca, in order to study the different rock types outcropping in the area, and their associated mineralization.

This project encompasses an in-depth study of various samples from different drill-cores located along a strategic line cross-cutting the entirely Penouta leucogranite, which has been used to develop a genetic model to explain the mineralization of Sn, Ta and Nb. The location and depht of drill holes selected to do this allow us to have more precise knowledge about the distribution of the ore in every granite facies, vertically and horizontally, vertically and horizontally.

Project applied for through the Ministry of Economy and Competition’s R+D Excellence Projects program in a 2014 tender. The work team responsible for this project is lead by the Polytechnic University of Catalonia, along with the participation of the University of Barcelona, the University of León and the Technical University of Oruro (Bolivia).

For the last three years, this project has aimed to research the possibilities of sustainable management for the mining and other waste generated in the Penouta mine, in order to find new applications in the glass industry. This way, we can not only obtain an additional financial benefit by treating the sterile waste from the metallurgy process as byproducts, but we can also obtain an environmental benefit: substantially reducing the amount of waste in dumps and landfills, therefore significantly reducing the visual impact that always comes to mind when people think of mining.

The basically siliceous nature of the waste generated at the Penouta mine makes it appropriate to research its application in glass-ceramic and glass materials. Therefore, while we implement this project, these materials will be categorized from a granulometric, chemical and mineralogical point of view, to determine the optimum conditions for developing new glass and glass-ceramic materials. Then we can characterize these new materials to evaluate their potential applications.

On the other hand, an environmental assessment will be made to determine the possible repercussions of evaluating these types of waste, helping make our mining operations sustainable and respectful of the environment.

This is a project that is part of the well-known EU Project “Horizon 2020”, called: ncreasing yield on Tungsten and Tantalum ore production by means of advanced and flexible control on crushing, milling and separation process.

The main objective of OptimOre is to optimize trituration, milling and Ta and W ore separation technologies during the mineral processing. To do this, new software models are used, which improve the fine-tuning and control of production processes, with an in-depth physical study of the processes, helping yield increase by 12.7% compared to current best production processes and producing energy savings of 5% relative to the best techniques available.

In this project, coordinated and led by a Spanish university (the Polytechnic University of Catalonia), different public and private organisms, both national and European, work hand-in-hand to be able to develop each of the strategic points, who will ultimately bring success to the three-year research project.

To do this, they also have a group of advisors and collaborators (engineering, consulting firms, mining companies and companies dedicated to manufacturing mineral processing and characterization equipment), among which are STRATEGIC MINERALS EUROPE, which has supplied material from the pond from the Penouta mine. A chemical, minerological and granulometric characterization will be carried out, which will help us determine the essential parameters that are needed to increase yield during processing.

After the mineral processing at the Penouta mine, we can obtain both a columbo-tantalite concentrate and a cassiterite concentrate. The cassiterite concentrate might still contain some Ta and Nb, since there are intergrowths of columbo-tantalite in those cassiterite crystals that are so small we cannot separate them using physical methods.

That being said, with a zeal for improving the quality of cassiterite concentrate, Strategic Minerals Europe became interested in learning more about how these concentrates behave when subjected to controlled melting processes. Thus, the goal was to segregate the metallic tin from the concentrate, leaving Ta and Nb as a slag, which could be characterized and tested for its potential later evaluation.

For this, we turned to two national research organisms who have a wide experience with these processes:

IK4-AZTERLAN: performed a study defining the theoretical enrichment possibilities of the Nb- and Ta-enriched waste using methods related to melting.

They have performed a thermodynamic study on the behavior of the different components of this concentrate after being subjected to melting. By combining different parameters, such as temperature, granulometry, percentage of flux, atmosphere (reducing or oxidizing), they can theoretically optimize the possibilities for enrichment. In a second phase, they attempted to verify these theoretical calculations using experiments that could transfer to an industrial process.
CENIM (National Center for Metallurgical Research): with the same goal in mind, they will take the traditional path of carbothermic reduction to separate the metallic Sn from the concentrate, leaving a Nb- and Ta-enriched slug. They will have to conduct a series of reduction fusions in the lab, with different variables, like the the coke/flux ratio for a certain temperature. The subsequent characterization of metallic Sn and the slag will allow them to determine whether or not a purification process is required to obtain the Nb and the Ta, if they are associated with other mineral phases. Once the process is optimized in the lab, they can conduct the same tests on a semi-industrial scale, which will allow them to verify the results from the first phase.

R+D+i Projects

Petrographic, chemical, minerological and petrogenetic studies on tantalum, niobium and tin mineralization in the Penouta Mine

Inertization of mining wastes, through its valorization as raw materials for the production of glass ceramics

OptimOre Project (Horizon 2020)

Smelting studies for Sn, Ta and Nb concentrates