## 1 Introduction  
Three-dimensional (3D) models of mines that depict the floor, walls and benches provide the basis for several types of mining management and safety applications, including slope stability assessment and monitoring, rock mass assessment, environmental assessment and volume calculations. Common techniques for mine mapping include standard survey techniques using Global Navigation Satellite System (GNSS) and electronic total stations, Terrestrial Laser Scanning (TLS) and more recently photogrammetric approaches based upon Unmanned Aerial Vehicle (UAV) surveys. Standard survey approaches are typically used for mine surveys; however, they do present difficulties when mapping large or complex sites, and can be time consuming and, therefore, expensive [1]. By comparison, TLS is a rapid technique for generating dense point cloud measurements of mine faces; however, the measurement quality is strongly dependent on the scanning conditions, including the scan configuration, surface geometry and reflectivity [2] and they often require repeat surveys from different vantage points for a complete model of the site. As TLS is a line-of-sight instrument, high cliffs or rock faces that exhibit complex morphology can result in occlusions and data shadows in the final surface model that must be removed during post-processing [3,4]. Drone or UAV photogrammetric-based surveys involve a digital photography collection from a flying UAV platform; these images have the characteristics of large overlap areas between sequential images, multiple viewing angles as the drone passes over the site and high ground resolution [1,5]. Mine surveys using UAV are advantageous in that they allow surveys of vertical rock faces to be combined with standard horizontal UAV surveys and ground-based photography, allowing a complete model to be created from photography taken with different orientations and scales [3,6]. For small simple mine sites, traditional survey techniques are cost-effective for quarry face mapping, but as the survey area gets larger or more complex, TLS or UAV techniques become more effective. It is a trade-off between the time taken for mission planning, accurate positioning of Ground Control Points and photogrammetric post processing of UAV data and the number of survey locations required, and time taken for a TLS survey of a mine. For large complex quarry or mine sites, UAV is the most effective mapping approach [3]. While these two approaches differ significantly, TLS provides high accuracy but is time consuming, while UAV is good for surveying large or complex sites, the joint use of UAV-based photogrammetry and TLS, whereby the photogrammetric approach is supplemented with additional input data from TLS, is increasingly being used to provide an accurate surface model of the quarry or mine [1]. In the present work, we wish to highlight the effectiveness of integrating different techniques and tools for better surveying and mapping, in a mine in a volcanic area, where parts of relevant outcrops are inaccessible or dangerous (e.g., [7, 8, 9]). In order to do this, we use an Immersive Virtual Reality (IVR) approach as designed by [PERSON] et al., (2020) [10] and integrated it with Geographic Information System (GIS) analysis for better mapping and assessment of geological features (e.g., [11,12]), as highlighted in the conceptual workflow for this paper shown in Figure 1. For Virtual Reality (VR) software, a brand-new software presented here for the first time called GeaVR was used, while for GIS software, a commercial one, called ArcGIS Pro was selected. The key site selected for the application of this integrated approach is the Metaxa Mine, located in the southwestern part of Santorini Volcanic Complex, Greece (Figure 2a,b). This is a well-known volcanological site where mining of pumice took place up until 1984.