Mineralización de oro en la franja aurífera de Veraguas, Panamá

Abstract

Gold mineralization in the Veraguas Gold Belt of Panama is hosted by calc-alkaline volcanic rocks of mid-Miocene age. The volcanic rocks range in composition from basalt to rhyolite and are intruded by coeval exogenous plugs and domes. Pyroclastic aprons surround the domes and host the ore deposits. The Remance mine, a vein and vein stockwork, has produced gold intermittently for over a century. Santa Rosa, a shallow epithermal stockwork and disseminated deposit, went into production in 1995. Gold discoveries in the Veraguas Belt focus attention on the exploration potential of hot spring systems and dome fields throughout Central America. RESUMEN:La mineralización de oro en la Franja Aurífera de Veraguas, Panamá, está contenida en rocas de edad Miocénica media, de composición calco-alcalina. Estas rocas tienen un rango de composición que va desde basalto hasta riolita y están intruidas por cuellos volcánicos y domos exógenos coevales. Cubiertas piroclásticas rodean los domos y contienen depósitos minerales. La mina Remance, un sistema de vetas y stockworks, ha producido oro intermitentemente por más de cien años. Santa Rosa, un sistema epitermal somero de oro diseminado y en stockworks, entró en producción en 1995. Descubrimientos de oro en la Franja Veragüense centran la atención en el potencial para la exploración que tienen los sistemas tipo fuente termal y en los campos de domos a lo largo de Centro América. INTRODUCCIÓNDepósitos de oro diseminado y en stockwork contenidos en campos de domos representan importantes objetivos para la exploración en la cuenca caribeña y el arco circum-pacífico. En América Central, el primero de estos depósitos en entrar en producción fue la mina Remance (Panamá), en 1989. Desde entonces, nuevos descubrimientos en los campos de domos han sido anunciados en Santa Rosa, Panamá (1,0 millón de onzas), Crucitas en Costa Rica (2,2 millones de onzas) y San Andrés en Honduras (0,85 millones de onzas). Los tamaños de los depósitos que se mencionan en este trabajo están referidos a sus recursos auríferos publicados al mes de octubre de 1997. Aún cuando depósitos de talla mundial (más de 5

Ecological and Health Risk Assessments of an Abandoned Gold Mine (Remance, Panama): Complex Scenarios Need a Combination of Indices

“…Au occurs as small inclusions within pyrite and marcasite, as well as free gold, disseminated within quartz, together with other accessory minerals in small quantities such as chalcopyrite, sphalerite, galena and arsenopyrite. Ag and As are found with Au, along with anomalous amounts of Sb and locally Hg [23]. Other polluting sources are represented by a mine gallery with its continuous water flow, a number of scattered dumps as a result of excavating trenches that evidently contain some proportions of exploited ore minerals and three tailing dams used to concentrate gold ore by means of cyanidation and containing high concentrations of PTEs (Cu, Zn, As, Sb, Ba, Hg, T-CN) according to studies carried out by González-Valoys et al (2021) [26].…”

“…The exploited mineralization corresponds to epithermal gold hosted in pyroclastic rocks, which include several veins distributed in an area covering approximately 10 km 2 [23] (Figure 1). Mining exploitation has occurred there intermittently since 1800, but we were unable to find details on its extraction processes.…”

“…Mining exploitation has occurred there intermittently since 1800, but we were unable to find details on its extraction processes. The Veraguas Mining Company produced 15,500 tons with 10.5 g of gold extracted per ton from the Remance mine during the 1800s; the Panama Corporation produced another 70,000 tons with 12 g of gold extracted per ton between the years 1923 and 1932 [23]. The last company to operate the site using the cyanidation process [22] was Minera Remance S.A., between 1989 and 1999 [23]; for this period, it reported cumulative production of 53,480 ounces of gold [24].…”

“…The Veraguas Mining Company produced 15,500 tons with 10.5 g of gold extracted per ton from the Remance mine during the 1800s; the Panama Corporation produced another 70,000 tons with 12 g of gold extracted per ton between the years 1923 and 1932 [23]. The last company to operate the site using the cyanidation process [22] was Minera Remance S.A., between 1989 and 1999 [23]; for this period, it reported cumulative production of 53,480 ounces of gold [24]. During this period, many complaints were filed regarding pollution of local water bodies and the Santa María River [22,24].…”

“…Presently (June 2021), there is a plan to reinitiate mining activity, which has led to local discord [25]. A drainage network runs through the area, and includes the Veneno stream, the Chitreca stream and the La Máquina stream on the slopes of Hill Tullido, excavated to exploit a quartz stockwork [23]. Possible sources of pollution in the area include mine excavations, which correspond mostly to surface trenches following mineralized veins.…”