Nikolaos Arvanitidis

7 minute read

Green minerals

The X-Mine research project focuses on using real-time mineral X-ray analysis to make exploration and mining more efficient and sustainable.

A fundamental reason why the X-Mine project exists and why the European Union is financing the project through the research and innovation framework program Horizon 2020, is that that the modern society and individuals use a lot more metals than a hundred years ago. You cannot destroy an element once it’s been created which means a lot of metals can be recycled, - but since the earth’s population is increasing, recycling only cannot provide enough metals to make up for the demand, and consequently, -primary metals have to be supplied by mining.

New ore bodies are becoming harder and harder to find and they are often only to be found at large depths and often also have a low content of metal to the tone of rock. Additional to these basic facts, the European Union consumes almost 25 percent of all mineral raw materials produced on earth, but only produce between three and five percent. This dependence on import makes our manufacturing industry very vulnerable and the only way to become more self-sufficient is to either reduce consumption or mine more metals.

To be able to extract metals the exact location and characteristics of the mineralization has to be known and described through exploration which is a tedious and expensive task since metals aren’t evenly distributed in the earth’s crust. Some countries may have plenty of zinc, lead and iron but can at the same time lack gold or cobalt.

One of the tasks in the X-Mine project is to demonstrate new methods that can make exploration more efficient. Basically, one has to understand that exploration is incredibly difficult. Roughly one in every thousand exploration permits results in a mine and therefore, if X-MINE can provide new tools increase efficiency in exploration, it is a good thing in all aspects.

Another important goal of the X-Mine project is more efficient ore extraction. More efficient extraction is important because it makes it possible to extract deposits with lower metal content. X-MINE will demonstrate how the exploration process can change with new X-RAY based technologies. Currently exploration is an expensive and long for the exploration geologists.   First areas of interest have to be selected by studying the general geology in the exposed part of the bedrock to try to figure out what parts of it have undergone potentially ore-forming processes. This geological mapping effort helps the geologist to recognize where to collect samples and in the next step, to decide where to collect samples below cover or at greater depths, by for example, diamond drilling.

The drill cores from exploration drilling are examined and interesting sections are cut, crushed, ground and sent on to laboratories, often in Canada or Australia for analysis to find the levels of different elements in the material.

Often the results of the analysis are returned after three to four weeks and then after interpretation, it is fairly common that one conclusion is that we should have drilled another 50 meters. At that point in time, the drill rig is often since long gone, the area might have been restored and the drilling season has come to an end because of weather. Next year, we return to the area and drill another drill hole, and then we go through the whole process again, but this time we might discover that we should have drilled further to the right or to the left. Often this repetition keeps going over and over again until we understand what’s down there… X-MINE project will demonstrate that it is possible to cut down on the time spent on exploration and to increase the efficiency in the exploration phase with new technology. Just imagine how much resources can be saved by getting production started in the right spot or if you can abandon a worthless project at an earlier stage.

Once the orebody has been explored, the extraction is initiated and can be done in several different, more or less efficient ways. Imagine a deposit where the value, for example gold, occur in a set of gold-bearing quartz veins no more than a few centimeters wide, grouped in meter wide zones. What if there are no machines available that are that narrow? Large scale mining, mechanized mining often means it’s necessary to extract the entire part of the bedrock that contains interesting metal along with large amounts of gangue on both sides. The mining cannot risk losing any of the metal, and all the excavated material(ore and barren gangue) needs to be transported to the surface, crushed and processed in a mineral processing plant and in the end of the process a few kilograms of metal is gained after mining of tons of gangue.

All the explosives, the drilling and the transportation of material costs a lot of energy and creates large voids in the bedrock at the same time as large amounts of waste is created and has to be managed. X-MINE will demonstrate how novel X-Ray technology can make the mining operation more efficient, and thus make it economically feasible to go deeper and to extract metals even when the metal grades are lower. The “X” in X-MINE stands for “X” as in X-Ray. The technology in the X-MINE project utilizes a phenomenon where an element hit by an X-ray beam, returns radiation with a wavelength specific to the element in question, the technology is often referred to as X-ray fluorescence (XRF), that makes it possible to identify the composition of the material being examined.

X-ray fluorescence (XRF) has long been used to analyze the surface of rocks but now, new methods have been developed that can make a rock transparent to X-rays, allowing them to penetrate all elements lighter than lead. And it is also possible to get analytical signals from elements ranging from sulphur, with atomic number 16, to bismuth, with atomic number 83. X-MINE will demonstrate technology that can see through a core sample, which is called tomography, and get analytical signals from inside the sample. With the new technology, it is possible to see where different minerals are located in a core sample and directly pinpoint veins of interesting metals and determine their metal content, without having to destroy the core sample.

The new method is also so quick, so that when applied to exploration drill core, the drill core samples can be analyzed and reported while the drilling is still in progress, revealing if you need to keep drilling or if you need to drill somewhere else instead.

In the X-MINE project the method and equipment, originally developed by project partner Orexplore, will be used to create better 3D geological models of deposits at four different mines, including Assarel Medet in Bulgaria, Lovisagruvan in Sweden, Skouriotissa in Cyprus and at Hellas Gold in Stratoni, Greece.

In parallel with the demonstration of the drill core tomography and analyzer, the X-MINE project will also bring the X-Ray technology over to use in a sorting plant where all the material extracted from a mine will be analyzed to separate rocks containing metal from gangue. Successful sorting means less rocks to crush and process and the process can focus on the material that actually contains metals rather than waste.

In total about 45 people from 15 different partners in nine different countries are involved in the X-Mine project, ranging from geologists, specialists in building thumbnail-sized sensors for the analysis device, mathematicians, and so on, to experts in 3D modelling of rock volumes of several cubic kilometers in size.

For more information, visit www.x-mine.eu or contact: Project in general: Jouko Malinen, Project leader ([email protected]) 3D-modelling: Ronald Arvidsson ([email protected]) Scanning: Kevin Rebenius ([email protected]) Sorting: Jacek Kolacz ([email protected]) Information: Stefan Sädbom ([email protected]

This project has received funding from the European Union’s “Horizon 2020 Research” and Innovation Program under grant agreement [730270]