subject: The development trend of the Gold Mining Equipment [print this page] The development trend of the Gold Mining Equipment
Gold Mining Equipment is perhaps the oldest mining activity around the world. Although copper can compete for that nomination, the gold extraction has attracted men of different races and social status toward its recovery. Talk about gold recovery is a subject related to the metallurgical process to be used and the equipment to be used. The latter issue has passed through a slow evolution since the first equipment used for its recovery.
The equipments to be used in the recovery of free gold comprise the gravimetric equipments which have been used in the recovery of free gold since the man recognized the importance of gold as source of power and richness. They made use of the difference in specific gravity between gold and other metals or minerals.
Gold Mining Equipment were developed under the concept of recovering gold as soon as It can be done because sometimes the opportunities of recovering can be less successful. One of the first equipment employed by old miners was the gold pan which is considered as the old-fashioned way to recover free gold in rivers and small streams found in forests and valleys. The gold pan is still the most widely used device for washing small placer samples. The pan is well suited for washing small samples but it is not well suited for handling samples over 15 kilograms or if samples are taken very frequently.
Other gravimetric equipment very employed is the called Sluice Box which can be defined as an elongated wood or metal trough equipped with traverse riffles through which alluvial material is washed to recover the heavy minerals. Sluice boxes are sometimes, but erroneously, called long toms. The function of riffles in a sluice box is to retard the movement of heavy minerals allowing them to settle while the lighter material flows on through the sluice. Carpeting is often used under the riffles to increase the recovery of fine gold. In some operations, mercury is placed in the riffles to enhance gold recovery.
The sluice box and its operative principles have been used to develop the Rockers and the Dry Washer. A rocker is a short, sluice like trough with curved traverse supports that permit it to be rocked from side to side. A flow of water, aided by the rocking motion, carries the material down the trough where the heavy minerals are trapped by riffles. Rockers have been used almost unanimously for washing samples by the dredging industry. A rocker requires less water than a sluice and is capable of recovering very fine gold. Dry washers are used in and regions where water is scarce and a dry recovery plant are proposed for production. The dry washer uses a bellows to blow air up through a sluice box with a porous bottom, causing the lighter material to progress down the sluice while the heavy minerals are trapped behind the riffles. In order for a dry washer to work efficiently, the feed must be very dry. Damp, sticky material cannot be processed until it is dried. Gold Mining Equipment
Other important equipments are: jigs, shaking tables and centrifugal concentrators, maybe, the last ones have been designed with the main idea of recovering small particles of gold which are a real problem due to they have a particular behaviour in a solid-water system.
