# Mineral Powder Extraction by the Natural Drying of Water from the Public Springs in Borsec
## 1 Introduction  
Borsec is a small town situated in a depression of the same name located in the Oriental Carpathian Mountains (Romania) at the eastern side of Giurgeului Mountain at an altitude of 880 m. The depression is influenced by the tectonics that resulted in faults during the post Pliocene sediment displacement during the volcanic and seismic activity that developedafter the Pliocene period [1; 2]. The geological admixture of sedimentary material with volcanic material within the tectonic faults represents the mineralization sources of the natural springs in the area [2; 3]. Some local geological drillings were carried out during the period from 1960 to 1970 revealing the complex stratigraphy of the Borsec depression involving two basic aquifers [4]. The first aquifer has a top layer formed by gray-black peat with clay intercalations with a depth up to 10 m. The following layer is situated between 10 to 20 m in depth. It is formed by a gray clay-sand admixture containing sericite chlorite mixed with crystalline shale based on quartz particles. Between 20 and 30 m in depth, gravel containing crystalline shale mixed with limestone is found, followed by gray clay intercalations from 30 to 45 m in depth. The next geological layer consists of massive deposits of gray-white dolomitic limestone down to 65 m in depth. The aquifer is situated at 65 m in depth sustained by the compact base of a dark dolomitic limestone layer ranging up to 80 m in depth. The second aquifer has a top layer of peat having a depth of about 5 m followed by a thick layer (5-18 m in depth) containing chlorite green shale intercalation. The following layer is formed by green clay with sand intercalation structured in a dense mass situated up to 30 m in depth where a complex layer begins, consisting of talcose deposits admixed with dolomitic limestone, which merely becomes an intercalation of chlorite and talcose with graphitic intercalation down to 40 m in depth. The layer between 40 and 50 m in depth contains green and gray clay-limestone tuff with silica sand intercalation. The geological layer beneath 50 m in depth is formed by dolomitic limestone which becomes a compact structure in the depth range of 75-80 m sustaining the aquifer at 60 m in depth. Rainwater infiltrates through all these geological layers interacting with the mineral matter. Literature data show that peat has ion-changing properties making it able to retain certain water impurities [5; 6]. Clay layers also help the water purification and enrich its mineral content with several ions such as Mg and Fe from the chlorite structure [7]. The granular matter of the dolomite-crystalline shale admixtures allows for water interaction with calcite and dolomite mineral grains. Calcite has a water solubility of 0.013 g/L at 25 \({}^{\circ}\)C [8] and dolomite of 0.013 g/L [9], partly facilitating the dissolution of the rock formations into the infiltrated waters, raising its mineral content. Thus, the mineral composition of the water strongly depends on the water amount infiltrated through the geological layers and on the partial dissolving of the calcite and dolomite formations along with the ion-changing behavior of peat and chlorite. Each of the two aquifers will generate particularized water depending on the spring flow rate and the local mineral interactions. The mineralized water is collected into the deeper aquifer and is subjected to interactions with the volcanic characteristics of the deeper geological formations of compact dolomitic limestone. These are in close connection with the volcanic deposits of andesite and pyroclastic rocks. Literature data reveal that the geological formations within the Borsec area are affected by the volcanic activity regarding the Ciomadu Mare volcano, which induces significant carbonated and sulfurous fumaroles [10].