EVALUATION AND DESIGN OF A MINE VENTILATION SYSTEM FOR MINDOLA DEEP MINE :(5220 L - 6365 L ORE ZONE) ZAMBIA: DETERMINATION OF SIGNIFICANT CONTRIBUTORS AND FACTORS

Abstract

The paper reports research findings on the evaluation and design of the end of mine life ventilation system for the 5220L – 6365L ore zone of the Mopani Mindola Copper Mine in Kitwe, Zambia. The purpose of mine ventilation is to provide suitable environmental conditions in working places. The objectives of the research were: firstly, the evaluation of the current mine ventilation system for the 4440L – 5220L ore zone, taking into account the aged ventilation system infrastructure and, secondly, building of a ventilation baseline database for design of the end of mine life ventilation system taking into account the planned increase in production, and subsequent increase in depth of mining from 1586m (current depth) to about 1930m (5220L – 6365L ore zone). In evaluating the current ventilation system and designing the end of mine life ventilation system the methodology involved, firstly, collection of the mine and equipment physical details as well as primary and secondary data of the current ventilation system by means of ventilation surveys, analyses, and computations as well as processing of obtained data so as to use it in the design of the end of mine life ventilation system. Findings were: High wet-bulb temperatures (in excess of or close to 31.0 o C) were recorded in several mining areas below 4440L; Low air volumes of 1.5 – 4.5m3/s and velocities of 0.6 – 1.5m/s (lower than legal/scientific baselines of 30.0m3/s and 4.0m/s respectively) were evident in a number of mining areas between 4370L and 4440L; Dust concentrations of ventilation air in almost all mining areas were compliant with the established legal and or scientific baselines of 100 ppm; Obnoxious gas concentrations both in the general body of ventilation air and diesel unit exhaust emissions were well below Zambian legal/global scientific baselines of 1000 ppm CO2 and 100ppm CO . The total quantity of air leakage was in excess of 224 m3/s (35 % of total downcast air). In summary, the computed heat loads in the current mining zone (4440L – 5220L) recorded that diesel engine equipment with a total heat load of 1,792.5 kW (49% of the total heat generated) was the highest contributor, indicating it to be the 127 most important variable. Secondly, eelectrical equipment (fans), exposed rock (strata), metabolism, and others accounted for 1,861.5 kW (51% of the total heat generated). In conclusion, reduction and or replacement of diesel equipment electrical equipment would bring about significant reduction in mine heat load, and reduce or eliminate the need for refrigeration of the Mindola mine workings at depth.