Modern Mining April 2022

MODULAR PLANTS

Plug and play doesn’t always pay For a mine looking to fast-track production, the modular process plant may seem to be the ideal solution – a pre assembled unit means quicker delivery time, installation and operation, all which, in theory, result in a better and quicker return on investment for the mine.

H owever, there are various engineering criteria that must be considered for an off-the-shelf process or materials handling plant, advises Freddy Mahlare, Head of Process Engineering at UMS Group. Ready-to-use modular systems are generally skid mounted onto portable platforms so the process equipment can be easily lifted, secured, transported and used as a unit. Mahlare says they are particu larly useful at mines in remote locations, those with approximately five years life of mine or less, and various pit ore processing sites. Manufacturing and quality control is done offsite, everything is deliv ered to the site, pre-assembled, at the same time, they are easier and safer to install, installation time is reduced, and a smaller team is required during installation. “Modular process plants may also be appeal ing to junior miners who have a desire to produce quickly and reduce the time spent on plant instal lation,” says Mahlare. “While these units have often proven successful in various applications, there are several things to be considered to ensure the system will perform as intended. “There is a misconception in the industry that modular systems are suitable for any processing application, but this is not always the case. The big gest consideration is that often standard design modular plants have a capacity limitation. “For example, if a mine wants a 20 000 t/pm

or smaller generic designed chrome process, a modular plant could be suitable for this application. However, if the same operation requires to operate at increased throughputs to this and processing/pro ducing challenging ores/products, then it would not just be a case of replicating the 20 000 t/pm module. In such an instance a modular plant design might not be suitable, as it would be possible to overlook vari ous engineering and process requirements, and the process operability could be compromised, resulting in increased operating costs and reduced efficien cies,” says Mahlare. He explains that the design of any process plant, be it modular or bespoke fixed, requires compre hensive engineering. Firstly, metallurgical test work is required to identify the type of ore, particle size, viscosity, whether the ore body is amenable or not, or if it is leachable if it is to be leached – essen tially, to identify if the ore body can be economically processed. The next step is to develop capital expenditure based on engineering process design criteria includ ing the mass balance, water balance, sizing of the associated equipment, pipes and tanks, control sys tem, etc. required for that specific plant. As part of the engineering process, the plant is to be laid out on structural and 3D drawings so the owner can determine from an operability point of view whether staff can safely access operation posi tions, such as manual valves and sampling points,

Freddy Mahlare, Head of Process Engineering at UMS Group.

46  MODERN MINING  April 2022