GERMAN TECHNOLOGY
requirements of the mining industry. The Loesche mill technology stands out as a dry closed loop grinding and classification process within one single machine. Its energy efficiency and flexibility provide optimal potential for solving the pressing challenges for the mining industry which is confronted with ever more depleting ore qualities and ever more stringent environmental regulations.
Over the last 15 years, Loesche has successfully installed several mills in hard rock applications like phosphate and industrial minerals. Now it has developed its high pressure grinding system to work in connection with downstream sorting processes for the iron ore and gold industries. The dry high pressure communition in the Loesche mill provides advantages for the liberation of the valuable components and hence facilitates efficient flotation and magnetic separation processes. Comprehensive feasibility studies – also utilising a specially developed containerised pilot plant to test the mill onsite at the mines – have shown the benefits for iron ore concentration up to DRI-super pellet qualities beyond 67 % Fe content. A Turkish mining company is now the first to use a Loesche vertical roller mill to grind and float a low grade
sulphide copper-gold ore. Dry and wet grinding technologies were compared in terms of grinding performance and product quality. The improved flotation performances of dry grinding products led to the decision to install a Loesche mill type LM 56.4 for this beneficiation process.
Better hydrocyclone clusters
Hydrocyclones and the associated clusters( also called annular distributors) are commonly known equipment types in the field of mineral beneficiation. However, depending on the geographical area as well as the application field, the designs of the clusters and the associated arrangement of hydrocyclones can differ significantly.
With more than 50 years of experience, AKW Apparate + Verfahren GmbH is used to dealing with two different designs of hydrocyclone clusters. Currently, the market situation shows one type of cluster to be mainstream, although the two existing designs illustrate different concepts, with pros and cons including economic impact that are worth reviewing.
In mining applications, especially for big clusters, the most common configuration is feeding of the feed tank of the cluster from the bottom, responsible for a uniform distribution of slurry. Hydrocyclones are installed vertically, with their underflow being collected in a large ring shaped launder. The overflow pipes end in an overflow tank, which is installed at the almost same level as the underflow chute.
Another existing design, used in mining but also popular in many other hydrocycloning applications, has the feed tank also fed from the bottom, but hydrocyclones are installed inclined with direction to the centre. Additionally, the overflow tank is located on top of the feed tank. The overflow pipe routing generates a positive effect to the separation.
“ In our point of view there are some advantages in the second configuration-type of the clusters, such as the underflow collection chute can afford to be more inclined and, above all, smaller. Therefore, the risks of sedimentation in the launder are minimised, hence reducing losses. Moreover, such
an underflow design requires less space, and also accounts for less tonnage and surface to be rubberised( when relevant), leading to lower cost. The access to valves for maintenance is better, because of not crossing the overflow pipes.”
Overflow pipes are shorter, leading to saving in weight and no negative influence in separation result due to possible suction effects in the first cluster type. Also, the total diameter of the cluster is smaller than the first type, allowing for a smaller footprint.
Wirtgen Surface Miners put through paces in South Africa
Wirtgen South Africa, the South African subsidiary of the Wirtgen Group, has put the 2200 SM Surface Miner to the test by conducting a series of demonstrations and trials under local conditions. Wirtgen South Africa recently demonstrated the 2200 SM Surface Miner, which has a cutting width of 2.2 m and a depth of up to 30 cm, to various South African mining companies.
Mike Newby, Mineral Technologies Manager at Wirtgen South Africa, commented:“ We wanted to show industry leaders how easily and effectively the 2200 SM mines coal and selectively mines material by separating thin seams so as to minimise contamination. The machine also cuts, crushes and directly loads the coal in a single operation. This means that delivering a final, sellable product without the
Strength
of steel and passion of men to protect equipment ´ s most important asset.
ERLAU TYRE PROTECTION CHAINS – NEVER WITHOUT!
Erlau AG Erlau 16, 73431 Aalen, Germany Tel. + 49 7361 595-0 TPC @ erlau. com
www. erlau. com
INTERMAT
PARIS
23- 28 April 2018 Stand: 5B N 027
MARCH 2018 | International Mining 13