Basically, natural gas, propane and fuel oil have been used in gold mining operations for power and heating. Propane and fuel oil are delivered by tank trucks to storage tanks on the plant properties. Natural gas has been used in certain circumstances when there is not availability of propane and fuel oil. In this way it is important to have an auxiliary supply of propane or fuel oil to insure a continuing fuel supply when cold weather results in an unusually high demand on the natural gas supply. Some variations in fuel oil requirements are due to the different temperatures employed for heating systems, the amount of building heat required and the availability of by-product steam from various sources. Major additional heating requirements may be an important economic factor of the gold recovery process and heat exchangers should be used for maximum economy. Another major source of increased fuel consumption is in the requirements for roasting refractory gold ores.
About steam requirements, some variation in its requirement is due to the range of slurry temperatures employed in special pre-treatment processes, which might typically range from 25 to 200 oC or to even higher values in autoclave circuits, although heat exchangers are employed in high-temperature circuits to minimize the heating requirements. Principal variations in steam consumption result from whether or not a plant needs steam for space heating or any special process. Gold operations with activated carbon processes include a stripping stage and the design must consider enough steam to satisfy this requirement. Even if the one steam plant is sufficient for all mill requirements, it has been advisable to have a stand-by boiler available for use when the main boiler in down for maintenance. One aspect very important associated with boilers and steam is related to the water treatment. It means that boilers needs at least softened water, otherwise the boiler will fail and the steam generation cost will be increased. When water is not treated, boiler pipes have incrustations of calcium carbonate and calcium silicate, which increase the thickness of the pipe and consequently, it is necessary more time and fuel to boil water. When this aspect is overlooked, unexpected problems and costs appear.