Jigging

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Jigging

Jigging is a method of gravitational preparation of natural resources, based on separation of mineral mixture on density in vertically oscillating water stream of variable direction. The end products of jigging are the following : concentrate with high content of useful component and wastes ( sometimes there is separated intermediate product consisting of aggregation of useful component with dead rock or from their mechanical mixture, the so called intermediate product).

Separation of material during jigging takes place as a result of periodical influence of the upward and downward of water ( pulsations ) on the layer of separating material ( the so called jigging bed), located on the sieve. Under action of pulsations the bed is alternately loosened and compacted , and the particles of different density mutually move on its height : with small density – into upper layers, with big density - into bottom layers. The formed layers of different density are separately removed as a concentrate, wastes and, sometimes, intermediate product.

Theoretical principles of jigging were laid by German scientist P. Rittinger. Peter Fon Rittinger (1811-1872) – Austrian mining engineer made some inventions in mining, for example, a drum for ore washing, etc., which were widely used.

In 1850 he was nominated as an adviser of department of engineering projects under ministry in Vienna, and in 1864 was appointed as a spokesperson on Austrian Mining Academies. Method of teaching in academies was changed according to suggestions of Peter Fon Rittinger. Rittinger published his “Enfarungen, which were issued as supplements to “ Oesterreichische Zeitung fir Berg-und Huttewensen”. In mining Rittinger was considered as established European authority. New theoretical description of jigging was connected with potential theory of jigging, where was considered not movement of separate particle , but stratification of all jigging bed tending to minimum of potential energy.

Mayer's potential energy theory is one of the most widely accepted theories describing jigging. While it represented a substantial contribution to jig theory, the potential energy theory can not be applied directly to describe real jigging operations. A modification to that theory has been made recently and is called the dispersion model of jigging. That model, however, is limited to describing jigging of particles of uniform size.
A procedure that uses the Monte Carlo technique and Mayer's principle has been developed, and is used to simulate jigging of particulate mixtures of variable size and density. It is demonstrated that for the case of monosize feeds with variable densities the simulation procedure provides results identical to those from the dispersion model. Further, in the case of binary-sized feeds, it is shown that a layer of fines accumulates in the top of the bed, while a greater proportion of coarse material is observed in the bottom of the bed.

Soviet scientists N.N. Vinogradov and E.E. Rafales-Lamarka ( the 60-th of 20-th century) considered jigging as a mass process in which not only strictly determinated factors act, but casual factors also.

Jigging is dealing with washing natural resources in wide range of size – from 0.1 ( alluvial ores) up to 250 mm ( anthtracites), and also different density – from 1400 ( coals) up to 15.000-19 000 kg/m3 ( gold and platinum). In the flowsheet of preparation plants jigging sometimes is a major method of preparation, but frequently it is combined with other methods.
Due to high specific capacity, small energy consumption, simplicity of applied equipment and comparatively high precision of separation, conceding on this factor only to heavy medium separation, jigging is referred to the most saving methods of preparation, especially in preparation of coals and ores of ferrous metals with large impregnationof useful components not requiring fine crushing.