Plans for the future scientific activities in the Pyhäsalmi mine

Abstract The Pyhäsalmi Mine is approximately 1,400 metres deep metal mine at Pyhäjärvi, Finland. This one of the deepest mine offers unique facilities and underground infrastructure for several purposes. For the exploitation of the infrastructure after the end of underground excavations there are plans to establish a Science and Research Centre in the mine. Different international studies and reports have proven that the Pyhäsalmi Mine area is an excellent site for underground physics experiments from both technical, infrastructural and scientifical point of view [1]. This feasibility has been shown, for example, by the extended site investigations at Pyhäsalmi Mine [2] which included, among others, analyses of the structural, physical and chemical conditions of the rock mass. The facilities of the mine are excellent, for example, for various kind of physics experiments due to the large rock overburden, but also for other fields of science. Therefore, during 2015 an open call process will be organized in which new experiments looked for to utilize the underground facilities. In this work we present plans for the future activities in the Pyhäsalmi Mine

Muography and geology:does it matter which continent you stand on?

Abstract The present work has one aim and one aim only: to increase the geological credibility of simulations of muon propagation in real-world rocks. We accomplish this by introducing five different sets of real-world geological systems. Our approach contrasts with the so-called “standard rock” approach, which uses a simplified rock composition as a proxy for geological materials. However, while the conventional approach relies on an assumed average geological composition, it fails to appreciate the complexity of real-world rocks, which indeed are extremely varied in both density and chemical composition. In contrast, each of the five geological systems we have used in our simulations is statistical in nature and represent an average composition of a massive number of similar type of rocks from around the world. The studied real-world geological systems were (1) upper continental crust, (2) bulk continental crust, (3) lower continental crust, (4) oceanic crust, and (5) oceanic upper mantle. Furthermore, water and standard rock were used as references as those are more familiar materials among astroparticle physicists. The simulations were conducted using the standard tools of Geant4 (muon attenuation in materials) and CORSIKA (muon energy in intensity distributions on the ground level), while the parametrized estimates were based on the works of Guan et al. (modified from the Gaisser formula) and Chirkin and Rhode (MMC code). The muon rates were compared to the experimental data of Enqvist et al. extracted in the Pyhasalmi mine, Finland

Muography and geology:does it matter which continent you stand on?

Abstract The present work has one aim and one aim only: to increase the geological credibility of simulations of muon propagation in real-world rocks. We accomplish this by introducing five different sets of real-world geological systems. Our approach contrasts with the so-called “standard rock” approach, which uses a simplified rock composition as a proxy for geological materials. However, while the conventional approach relies on an assumed average geological composition, it fails to appreciate the complexity of real-world rocks, which indeed are extremely varied in both density and chemical composition. In contrast, each of the five geological systems we have used in our simulations is statistical in nature and represent an average composition of a massive number of similar type of rocks from around the world. The studied real-world geological systems were (1) upper continental crust, (2) bulk continental crust, (3) lower continental crust, (4) oceanic crust, and (5) oceanic upper mantle. Furthermore, water and standard rock were used as references as those are more familiar materials among astroparticle physicists. The simulations were conducted using the standard tools of Geant4 (muon attenuation in materials) and CORSIKA (muon energy in intensity distributions on the ground level), while the parametrized estimates were based on the works of Guan et al. (modified from the Gaisser formula) and Chirkin and Rhode (MMC code). The muon rates were compared to the experimental data of Enqvist et al. extracted in the Pyhasalmi mine, Finland

Muography and its potential applications to mining and rock engineering

Abstract Muography is a novel imaging method using natural cosmic-ray radiation for characterising and monitoring variation in average material density in a diverse range of objects that cannot be imaged by conventional imaging techniques. Muography includes muon radiography and muon tomography. Cosmic-ray-induced muons were discovered in the 1930’s, but rapid development of both muographic techniques has only occurred in the last two decades. With this rapid development, muography has been applied or tested in many fields such as volcano imaging, archaeology, underground structure and tunnel detection, rock mass density measurements, cargo scanning, imaging of nuclear waste and reactors, and monitoring of historical buildings and the inside of blast furnaces. Although applications of muography have already touched mining and rock engineering, such applications are still rare and they are just beginning to enter the market. Based on this background, this paper aims to introduce muography into the fields of mining and rock engineering. First, the basic properties of muons are summarized briefly. Second, potential applications of muography to mining and rock engineering are described. These applications include (1) monitoring temporal changes in the average material density of fracturing and deforming rock mass; (2) detecting geological structures and isolated ore bodies or weak zones in mines; (3) detecting a reservoir or boulders during tunnelling or drifting; (4) monitoring caving bodies to search remaining ore; (5) evaluating and classifying rock masses; (6) exploring new mineral deposits in operating underground mines and their surrounding brownfields. Finally, some issues such as maximum depth muons can reach are discussed

CallioLab in DULIA, the European network of deep underground laboratories

Abstract The Deep Underground Laboratories in Europe have started a networking activity project DULIA (Deep Underground Laboratory Integrating Activity), which provides a forum for a joint assessment of scientific proposals that plan to utilize the Deep (over 1 km of mass water equivalent layer of rock) Underground Laboratory (DUL) facilities, in EU countries. During 2016, Calliolab in Pyhäsalmi mine starts participating as a the newest member in the DULIA network, the other four laboratories being located in Gran Sasso (Italy), Boulby (UK), Souterrain de Modane (France/Italy) and Canfranc (Spain). From the physics research point of view, the DULs are currently the only viable facilities to conduct many types of astro-particle physics experiments, such as neutrino detection or direct observation of dark matter particles, because the cosmic ray background clouds the possibility to detect weakly interacting particles on the surface. In this presentation we discuss the characteristics of the DULIA laboratories and make short review of the current Deep Underground laboratory infrastructures on a global level. We also review the other DULIA activities, such as the standardization of background radiation assessment methodologies, safety instructions, sharing best practices, education and organization of joint workshops for the users

New underground laboratory in the Pyhäsalmi mine (Calliolab) and plans for the future scientific activities

Abstract CallioLab is located in the Pyhäsalmi Mine, in central Finland. The Pyhäsalmi Mine is a copper, zinc and pyrite mine being the deepest active metal mine in Europe with the main level at 1410 meters. The infrastructure is excellent offering two accesses by an elevator in 3 minutes or by a car 11-km long truck-sizes drive-way. There are among others, office rooms, storage halls, repairements workshops for mechanical and electrical instruments, and a lunch restaurant which can be used for meetings of several tens of participants. To make use of the infrastructure after the end of underground mining operations the plans for establishing a Science and Research Centre in the mine have started realizing. Different international studies and reports have proven that the Pyhäsalmi Mine area is an excellent site for underground physics experiments from both technical, infrastructural and scientifical point of view [1]. This feasibility has been shown, for example, by the extended site investigations at Pyhäsalmi Mine [2] which included, among others, analyses of the structural, physical and chemical conditions of the rock mass. Water analysis have also been done [3]. The facilities of the mine are excellent, for example, for various kind of physics experiments due to the large rock overburden, but also for other fields of science. Therefore, first round of an open call process was organized during 2015 and there is a new round during 2016, in which new experiments will be looked for to utilize the underground facilities. In the present work we present a new underground laboratory, CallioLab, and plans for the future activities in the Pyhäsalmi Mine

Technical characterization of Calliolab, the new underground laboratory for physics research in Pyhäsalmi mine

Abstract The development of the infrastructure for scientific work in the Pyhäsalmi mine is currently administered under the Calliolab project, which is managed by a consortium of the Universities of Oulu and Jyväskylä and regional organizations. A new laboratory has been developed in one of the tunnels at 1430 m depth in Pyhäsalmi mine. At this depth the cosmic-ray muon flux is attenuated down to one ppm compared to that on the surface, making the new laboratory an excellent location to conduct astro-particle physics research and material testing, which require ultra-low cosmic-ray background environment. The floor area of the new laboratory, is currently 120 m² and the average height is 9 m providing the volume of 1080 m³ for working space. The laboratory is located 400 m from the main service level of the Pyhäsalmi mine, which is accessible with an elevator from the surface. The laboratory is also connected to the 11 km long maintenance road and it is accessible with a truck. In this presentation we discuss the current status of Calliolab and it’s technical characterization, such as radon and other radiation background monitoring, ventilation, electricity and the isolation of the laboratory from mining operations We also review the main results from the FP7 design study for utilizing the mine for major neutrino physics experiments. 19.2 Particle and Nuclear Physics Poster 22

High-multiplicity muon events observed with EMMA array

Abstract High-multiplicity data, collected with a segmented scintillator array of the cosmic-ray experiment EMMA (Experiment with Multi-Muon Array), is presented for the first time. The measurements were done at the depth of 75 meters (210 m.w.e.) in the Pyhäsalmi mine in Finland. EMMA uses two types of detectors: drift chambers and plastic scintillation detectors. The presented data were acquired over the period between December, 2015 and April, 2018 using 128-800 plastic scintillator pixels probing the fiducial area of ˜100 m². The results are being interpreted in terms of CORSIKA simulations. Several events with densities in excess of 10 muons per m² were observed. At the next stage of the analysis, the high-multiplicity events will be matched with precision tracking data extracted from the multi-layer drift chambers of EMMA. Observation of high-density muon bundles was first reported by the LEP experiments: DELPHI, L3+C, and ALEPH. More recently, the ALICE experiment at CERN has provided new cosmic-ray results together with improved interpretation benefiting from the updated cross section values extracted from LHC results. While the tracking performance of ALICE is superior to EMMA, the duration of ALICE cosmic-ray measurements is very limited. Over the period of 2010–2018 the total exposure was only 93 days while EMMA, having a similar overburden provides a larger footprint and collects data continuously