2033 Pmh: planned hourly production (m3 in situ/hora) UCS: uniaxial compressive strength of the rock mass (MPa) Tr: minimum delay time between holes with electronic detonators (ms) L: hole depth (m) T: stemming (m) VOD: detonating wave velocity (m/s) Cp: P wave velocity in rock mass (m/s) 2. CASE STUDY The Brucutu mine is located in southeastern Brazil, in the state of Minas Gerais, where occur meanly Itabirite and hematite ores with Fe > 50% (Campos Gonçalves G.M., 2020). 2.1 Cost minimization at the Brucutu mine At the Brucutu mine, friable itabirites, canga, and intrusive rocks occur predominantly, with compact itabirite and hematite present in smaller proportions (Figure 2). The lithology at the Brucutu mine is mostly friable, with compact material being only slightly predominant, as observed in the current pit areas. Figure 2 – Geological context of Brucutu mine The lithological and geotechnical characteristics of the rock masses at the Brucutu mine are classified into three lithology groups: friable, semi-compact and compact (Table 1).
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