The excavation of ramps and tunnels often requires high-speed development with [or without] the use of high-energy mining equipment such as loaders, dump trucks, TBiUs and roadheaders. This highspeed development creates a challenge in termsofprovidingasafe and productive workingenvironment. For exnmple, heat from continuously exposed surrounding rock, heatfrom bruken rock, heatgenemted by mining equipment, potential inflows of hot ground water, pollution /%orn associated diesel equipment, and the distance of the advancing face from fresh through-ventilation all have to be taken into account when designing ventilation systems for high-speed ramp and tunnel developments. Thispaperdiscusses methods of achieving acceptable environments at the face and along the length of the tunnel. The methodology has been successfully implemented in the development oflong[up to 20 km]TBMdrives in the Lesotho Highlands Project and in miningprojects in hot rock using drill-and-blast methods as well as in mechanised methods using continuous miners and roadheaders. The determination of heat loads includes calculation of the heat flow within the surrounding rock, evaluation of the operating cycle of the equipment and the contribution to the ovemll heat load of the broken rock as it travels out of the tunnel. The &termination of heat loads from surrounding rock in new tunnels required a modifiation of the algorithms generally used for established excavations. Tkpaperalso
examines the use of for example, mobile duct and fan systems to ensure that fresh air is delivered to the specific areas where workers are located.