Deposit types Marmato is interpreted to be a porphyry hosted gold deposit with shallow epithermal and deeper mesothermal features and this interpretation has informed the exploration and mining plans. The Upper Mine is distinguished by a sulfide rich, structurally controlled system of veins and veinlets of pyrite, arsenopyrite, iron-rich sphalerite, pyrrhotite, chalcopyrite, and electrum veins associated with biotite, sodic-calcic, and epidote-chlorite-carbonate alteration. Mineralization Marmato mainly comprises northwest and west-northwest trending veins and veinlets, with intermediate sulfidation epithermal and mesothermal mineralization styles transitioning with depth from the Upper to the Lower Mines. The veins outcrop at the surface, and within Aris Mining’s mining titles, mineralization extends vertically over 1,100 m and remains open at depth and along strike, and has a high expansion potential from future underground drilling programs. The Upper Mine mineralization is characterized by epithermal mineralization comprising wider, parallel, sheeted, and anastomosing sulfide rich veins and veinlets with minor quartz, carbonate, pyrite, arsenopyrite, iron rich sphalerite, pyrrhotite, chalcopyrite, and electrum. Broad zones of intense veinlet mineralization hosted within a lower grade auriferous porphyry stock are locally referred to as “porphyry pockets” or “porphyry” mineralization. In the Upper Mine, interpretations of 94 different veins and 53 zones of disseminate ........

The Upper Mine is in operation and developed to the 1,000 m elevation utilizing three different mining methods, separated into two distinct zones.

The Upper Mine is the mineralized vein material between 950 m elevation to 1,300 m elevation, and is currently in operation and mined using conventional cut and fill stope methods at a mining rate of 1,250 tpd. An area at the base of the Upper Mine between the 950 m and 1,050 m elevation, referred to as the Transition Zone, occurs where the deposit changes from narrow vein style mineralization to large porphyry style mineralization. Mining in the Transition Zone is by long hole stoping and drift and fill at a mining rate of 350 tpd.

Upper Mine mining methods
Mine layout and access
Mining at the Zona Baja mining title extends approximately 300 m vertically and 900 m along the vein structure, in the area referred to as the Upper Mine. The mine has been developed with level accesses proceeding horizontally from the main portal at the surface on Level 18 to horizontal cross cuts that provide access to the veins. There are currently six production levels and one level in development, with the highest production level at Level 16 and the lowest production level at Level 21. Each level is spaced 50 m apart vertically, with the exception of Level 20, which is 60 m from Level 19. Level 18 is the main haulage level and the primary access for the mine. A track drift provides the main haulage for all material. ........

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