This thesis discusses about feasibility of battery operated mobile equipment in Underground Hard Rock Mining environment. Both operation and maintenance are covered. The scope includes drills (development-, production- and rock support drill rigs) and loading and hauling equipment (LHDs and trucks). The study was ordered by Jani Vilenius, Research and Technology Manager, Product Development & Global Technology / Sandvik Mining. The main needs for seeking alternatives for diesel operated equipment are constantly more stringent diesel exhaust requirements (for example Tier4) and EHS aspects. The mine’s ventilation flow rate is closely linked to the amount of diesel kilowatts in the mine and by using electric / battery drives the flow rate could be reduced. This will lead to lighter ventilation infrastructure and lower ventilation power needs thus reducing costs of ventilation. Generally the mine’s ventilation comprise 40 to 60% of the total mine power consumption. The technological maturity of high energy Lithium Ion batteries is improving all the time. Currently there are a few credible suppliers that can deliver commercial components for mobile equipment manufacturers. Most suitable battery chemistries for underground mobile equipment were found to be Lithium Titanate Oxide (LTO) and Sodium Nickel Chloride (SoNick). Variable Frequency Drives (VFDs) have also improved significantly within past few years and the offering starts to be on a fairly good level. Batteries and VFDs have been the restricting factors of keeping the battery operated units at the design tables. Other components are widely commercially available and the maturity is at a good level. Drills are ready to adopt battery tramming (e-drive) technology right away. The drill and blast working method is that cyclic that there is plenty of room for charging periods during drilling. There are more challenges to find mature enough solution for Loading and Hauling equipment (LHDs and trucks) where the power and energy needs are much bigger. Utilization rate of LHDs and trucks is so high that the charging needs to be fast in order to maintain adequate productivity. Suitable, ready-made fast charging components are not currently commercially available and the load for the mine’s electric supply network becomes somewhat challenging. In many cases the electric infrastructure needs to be strengthened to be able to feed a fleet of e-drive units.