By adopting the green mining concept, the mining industry seeks to respond to the current societal objective of supplying the mineral raw materials necessary for economic development while minimising the ecological footprint. To accomplish environmental recovery simultaneously with mineral exploitation, as well as to take advantage of mine waste, this study proposes a new solution that includes the construction of a tunnel to access the mining area. The concept, developed with topographical and geological data, was tested for the Bled El Hadba phosphate deposit. The extraction volumes were estimated by considering all the technical and legal aspects of the exploitation. The results showed that the best location for the tunnel is on the non-mineralised bottom of the mine and placed after ore removal. The tunnel is then progressively covered by mine tailings as it is extended. This concept is applicable to sub-horizontal ore deposits. We show that the solution is feasible and allows full site recovery at the end of the open-pit mining phase.

Mining industry importance stems from the fact that it forms the basis of all materials used by humankind, including the agro-industrial sector, where products such as phosphates are behind a significant part of all modern agriculture. Despite its high economic importance, the constraints of its activity make it be considered one of the most challenging and dangerous industries. The main optimization problems in open pit mining design consist on the determination of the ultimate pit limit for exploitation, and mining block sequences for the production schedule, where safety management decision system needs to be integrated. The proposed protocol provides the procedure that will be used to conduct one or more systematic reviews according to the PRISMA statement, to prove the effectiveness of optimization solutions on open pit mining production and occupational safety. The search will be carried out in eight electronic engineering databases, using eight combinations of appropriate keywords for the topic to achieve the main goal. The selection process, data extraction, and data synthesis are described. advantages (improvement in mine planning and safety in the long and short term), the effectiveness of implementation (cost and time). Outcomes of this study will contribute to the mining industry through research in order to improve mine planning and safety in long term and short term.

The solar quiet variation (Sq) observed at observatories near the latitude of the Sq vortex focus is difficult to assess because it is affected by both the geomagnetic activity level and the dynamics of the ionosphere and the upper atmosphere resulting in changes of the Sq ionospheric vortex shape and position. The use of only geomagnetically quiet days (QD) to calculate Sq for a given month can, to a certain extent, remove the effect of geomagnetic disturbances; however, the effect of the atmospheric dynamics still needs to be taken into account. The Sq vortex shape and position can be acquired from the horizontal vector of the geomagnetic field measured at geomagnetic observatories located in the European-African sector between 10ºN and 60ºN using vector rotation or calculating equivalent currents. Here we present results of a comparative analysis of two methods to extract Sq variations from the observations of the earth geomagnetic field. The analyzed data are measurements of the geomagnetic field done between 2007 and 2017 at the Coimbra Geomagnetic Observatory (COI, Portugal) located near 40ºN.The principal component analysis (PCA) based Sq curves are compared with the standard ones obtained using 5 international QD per month. For most of the analyzed years for the X component, the second PCA mode was identified as Sq variation whereas for the Y and Z components for all analyzed data sets the first PCA mode was identified as Sq variation. We studied differences and similarity of the PCA and IQD based Sq in relation to (1) the average geomagnetic activity level and (2) Sq vortex shape and position relatively to COI.