The drill cores pave the way in the geologists’ work
The geologists are the first in a mining project to discover new copper deposits in the rock. Here, Max and Elvis from Viscaria’s geological team share their experiences of prospecting for ore—and the joy of finding a quality drill core.
─ Before we plan a drilling operation, we always examine the geological data available for the area. In the Viscaria project, we can benefit from the extensive drilling conducted by other companies in the past, says Viscaria’s group manager for the geology team, Max Kröckert
Certain qualities are particularly beneficial for a geologist. Naturally, you need the right education, but it’s also a plus if you’re methodical and enjoy solving technical challenges both out in the field and in the office. Exploration and prospecting are essential aspects of the geologists’ work. However, even though the work is groundbreaking in many ways, it’s rarely done haphazardly.
During drilling operations, so-called drill cores are extracted from the ore body. These cores are samples that indicate the degree of mineralisation in the ore. In the cores, geologists also search for signs and vectors indicating additional mineralisations nearby. Such signs could be veins of carbonate or layers of magnetite. This work is crucial as it lays the foundation for where the mining project and processing plant will be located.
─ The rock and its levels of mineralisation determine where the facilities should be established. The best feeling for us geologists in the Viscaria project is when we discover a fresh drill core with a beautiful copper mineralisation,” says Nsioh Elvis Nkioh, geologist at Viscaria.
The foundation for a safe mining environment
The work of geologists lays the foundation for other parts of the project and is crucial for building a safe mining environment. The team maps where the rock is strong and where there are faults, pockets, or fragile areas. This information is then used by mine planners, who determine the placement of tunnels and how they should be reinforced.
Up to today, geologists in the Viscaria project have logged copper mineralisations all the way from the surface down to a depth of 1 kilometer, and so far, they have not found an end to the mineralisation; it is what they call “open” in all directions.
A kilometer below the surface
─ Through diamond drilling, we extract 47-millimeter-thick drill cores. These core samples are placed on logging tables and then evaluated by the geological team. Each drill core is a collaborative effort from planning to sampling, says Max.
From the core, it is possible to obtain a wealth of information about mineralisation, rock types, and—most importantly—metal content. Many geotechnical parameters are logged to determine the rock’s strength and mechanical behavior. These values are crucial for building mining infrastructure with a safe working environment. A good drill core is a treasure in the geologists’ work because it serves as a map for both safety planning and ongoing work.
Core drilling in Norrbotten
Within the geological team, there is a multitude of nationalities represented. One explanation is that geologists who want to work on large mining projects must be prepared to travel to where the ore is found and move on to the next job when the mining project ends. Thus, Viscaria’s geological team has a wealth of experience from different work environments, and they note that Norrbotten has its unique characteristics as a workplace.
“Here, we must adapt our work to the changing seasons. Winter gives us access to areas that are otherwise too soft and wet to place a drilling rig, meaning we drill in different areas during summer and winter. During summer, the wetlands offer their own challenges in fieldwork, not least due to the abundance of mosquitoes! On the other hand, an advantage is Viscaria’s proximity to Kiruna and adjacent infrastructure. Those living in the Mining Area have a great acceptance and understanding of mining, which is very positive. These conditions are rarely found in other mining projects,” concludes Max.
Facts
Viscaria’s copper ore has a concentration ranging from 0.4 to 2 percent, with an average of approximately 1.2 percent. This places Viscaria’s mine at a relatively high level of mineralisation compared to other copper projects, with more than double the average grade of the world’s copper mines. The so-called resource drill holes (which define an already discovered ore body) extend to a depth of about 500 meters. Exploration drill holes can extend down to 1,000 meters deep. Viscaria’s A and B zones extend over an area of 4 kilometers horizontally. Currently, the mineralisation in the D zone extends over a distance of 1.5 kilometers. There are 7 kilometers of magnetic anomaly in the area, indicating that the D zone may continue to grow.