A current trend in mining is towards lower grade deposits when easy to access mineral deposits are depleted in the world. Therefore, to make the current deposits accessible, a cost of mining need to be economic. Costs can be decreased in equipment and mine planning to maximize the availability and utilization of equipment for example by decreasing travelling and hauling distances in daily production. Ore passes are one of the possibilities to decrease hauling costs when mine is evolving the greater depths.

Ore pass design and placement is conducted using modified Bieniawski’s design strategy for rock structures. Thesis studies in detail all parameters affecting to the ore pass design and placement. With the strategy and data available from mine and literature, a case study for Kittilä Mine had been carried out.

Data collection from literature review and data acquired from the mine site was made and applied in the Bieniawski’s design strategy. Production related factors were weighted more in the design process in order of mining to assess the ore pass design and placement. The location and design of the ore pass were optimized using a state-of-the-art technology and best practices in combination with mathematically optimized location.

Via strategy it was possible to identify the project risks, technical viability and feasibility of the ore pass project. Case study shows that via applying the design strategy it is possible to show that mine can benefit from using ore passes in its operations and that ore passes are financially viable solution if ore passes can be operated the way presented in this study.

Blasting operations form a central part of any hard rock metal mining operation, and are, given its inherent hazards, critical in ensuring safe mine working environments. In order to improve workplace safety in such operations, it is important to select the right explosives and technologies, to issue rules and procedures and to offer adequate training and ensure awareness of hazardous situations. Because multinational mining companies work under different jurisdictions, they have to comply with different rules with different regulators. New Boliden is a Sweden-based mining and metals company, involved in both the extraction, refining and recycling of primarily base metals, with mining operations in Sweden, Finland and Ireland. Given that their aim is to have no Lost Time Injuries (LTI’s) at any operation within the company and that there are prospects of further international expansion and technological developments, it is important to develop working practices that both comply with various legal requirements, are practically usable and lead to a very safe working environment. The aim of the research is therefore to identify applicable legal requirements, technologies and working methods, in order to see if different working practices are compliant with these legal requirements, and whether these different requirements and practices can help to meet both the requirements of different regulators and Boliden’s own mission objectives. This research has identified the legal requirements applying to mining operations in Sweden, Finland and Ireland, and compared working practices in several mines, operated by Boliden Mineral AB in these countries. With a comparable number of relevant legal sources, the legal structure on explosives safety requirements is generally similar. However, Nordic legislation generally puts more generic responsibilities on the employer, whereas Irish regulations are more specific. Blasting requirements in Finland and Sweden are mostly similar and apply to underground and surface mining operations and civil engineering, whereas Irish legislation is tailored specifically to underground mining operations. Significant differences can be seen when comparing explosives handling, in particular explosives storage, Ireland has a very different approach in this respect, which may be helpful in improving safety performance in Nordic mines as well. The main technologies influencing the explosives handling and blasting safety performance are considered to be the initiation systems used, the reliability of explosives and successful implementation of a digital track&trace system. No events leading to human injury have occurred following the utilisation of explosive materials in Boliden Mines in the past ten years. To get a good impression of problematic issues, using both Boliden and international data, it was found that the main types of explosives- and blasting related incidents are misfires, flyrock, toxic fumes and early detonation. Fault Tree Analysis, adapted forms of reliability modelling and the bow-tie method have been used to identify critical parts of the explosives handling and blasting process, based on available statistical data. For more critical cases, root causes of these failures have been identified. Critical activities are these surrounding evacuation of the blasting area, material failures and explosives materials being unguarded. Most incidents appear to be caused by failures in communication between different departments and insufficient awareness of existing safety procedures. Considering that there is overlap between the various operations in terms of legal requirements and practices, especially requirements with a European background, explosive materials used and operational- level working methods, it is judged to be useful to more closely align these practices, since learning from each other’s practices might improve safety levels. Also, alignment of track&trace systems, and the adoption of electronic initiation systems seem to be beneficial in this regard. It is deemed less useful to align more typically national requirements and practices, such as permitting and licensing procedures. In order to be able to exchange best practices, company-wide safety guidelines and reporting based on a clear distinction of responsibilities per activity are recommended. The main conclusion therefore is that alignment of existing safety practices and technology use is achievable given the various legal and operational constraints and is expected to ensure a zero-LTI explosives handling and blasting safety performance.

Nowadays more attention to environmental-friendly sources of energy has been given, aiming to slow down and counteract the damage to the ecosystem product of the abuse of fossil fuels. Different technologies on energy production, solar, wind, tidal, geothermic, etc., have been researched with the additional challenge of how to store it.
From the different types of energy, heat represents a basic need in countries where the climate conditions lead to long and cold periods, namely countries at high latitudes where a big part of the produced energy is destined to household and district heating.
The Academy of Finland implemented the New Solar Community Concept project to research the development and application of alternative technologies for production and storage of energy. The use of the local geological domains has been considered as a possible solution for seasonal and long-term energy storage, specifically heat. Aalto University participates in Tackling the challenges of a Solar-Community Concept in High Latitudes by researching the seasonal storage of thermal energy in the ground simulating and assessing thermal flow for different borehole heat exchangers arrays.
To do this, numerical models have been implemented, special attention to the Weak Form Equations (WFE) and the Heat Transfer in Pipes (HTiP) models. These models are evaluated using the COSMOL® Multiphysics software, each of them with advantages and disadvantages over the other.
An in situ experiment has been performed in Aalto’s research tunnel to validate the results of the numerical models. The aim of the experiment was to assess the performance of the models based on the result comparison between the simulated and the observed data under controlled conditions.
The experiment consisted of a single U-pipe borehole heat exchanger operating under seasonal conditions. Two phases were defined, heating and cooling. In the first phase, a constant heat flux is provided to the rock by circulating a heated carrier fluid in the BHE. In the second phase, the circulation is stopped allowing the rock to cool down under normal conditions. The heat field in the rock was tracked with a monitoring borehole one meter away from the heat source. Several digital temperature sensors were installed at the monitoring point in customized equipment referred in this work as Thermal Multisensor Probes for this purpose.
The comparison made between model and observed results returned an acceptable accuracy of the predicted values of the models for the heat flow in the rock mass. Additionally, it was identified the WFE model can be improved by calibrating the borehole thermal resistance parameter in the equations, parameter that must come from experimental data. Finally, it was seen that the few discontinuities present across the boreholes had a low impact on the flow of heat through the rock for this experiment.
Currently, the tuning of the numerical models is being performed at Aalto University by increasing the weight of different parameters in the models matching the results of the experimentation process.