cmd consulting pty ltd provides eco-comminution® specialist services to the minerals industry. A futuristic approach to designs incorporating HPGR and sustainability are key areas of consideration and include HPGR modelling and simulation, eco-comminution® circuit design, HPGR test work and analysis, energy reduction analysis and HPGR ore characterisation for pilot plant test trials. Other areas of competency include crushing and grinding, semi-autogenous grinding, HPGR vs SAG mill trade off studies, Carbon emissions equivalent reduction analysis, direct and indirect energy reduction analysis. Comminution circuit design reviews.

cmd consulting pty ltd is capable of managing assignments from initial comminution test work and ore characterisation through to comminution circuit design and evaluation to feasibility studies, engineering design for new and upgrade projects. Greenfield conceptual and scoping study in comminution circuit design. Project reviews and evaluations for all mining groups. Computer modelling and simulation of comminution circuits

cmd consulting pty ltd has specialised in the area of eco-comminution® circuit design incorporating HPGR. Comparative analysis based on ore characterisation and alternative conventional circuits is an area which is not clearly understood.  Capabilities include power modelling and efficiency assessments of SAG milling circuits and the ability to design a circuit from core ore characterisation test data.

HPGR ore characterisation test work

cmd consulting pty ltd specialise in ore characterisation for HPGR. Results of ore characteristics tested in this manner are used in validated HPGR models for the purpose of HPGR circuit design and scale up considerations.

Parameters which are readily obtained from the laboratory scale HPGR calibration tests. These data provide the model with useful data and give strong guidelines on the most appropriate power efficient circuit for the ore in consideration. HPGR pilot plant testing is thus reduced for major projects and can be eliminated for smaller projects. For larger new projects, full pilot plant studies are recommended. These can be arranged and supervised by cmd consulting pty ltd, using the facilities of JKTech.

For ongoing plant operations, plant surveys and ore characteristics are required to allow establishment of suitable models.  JK Drop Weight testing as well as Bond and SMC testing® is recommended in order to provide the data to model selected circuits in JKSimMet. Using these available tools, and published power models, the power efficiency of existing mills can be determined and recommendations made for improvement where warranted. Power predictions for large autogenous and semi-autogenous mills can be made, and variations in power with changes to ball load and speed can be forecast. These features are particularly useful in assessing the correct mill sizing for a project in which changes to the mode of comminution are envisaged.

Modelling of comminution circuits

The JKSimMet or Limn simulation packages allow mass balancing and modelling of existing crushing circuits from survey data. This allows examination and optimisation of the performance of the circuit and evaluation of proposed changes. A variety of crushing machines can be modelled, including gyratory, jaw and cone crushers, rolls and impact breakers.

For conceptual studies of new processes, cmd consulting work closely with the HPGR  equipment manufacturers to determine the appropriate choice of machines and the best configuration of the circuit to meet client requirements. Equipment sizing and capacity requirements can be derived, together with related screening applications where required. Flowsheets, mass balances, conceptual general arrangement drawings and capital and operating cost estimates can be provided to enable investment decisions to be made.

Optimisation of grinding circuits and process audits

The basis of the simulation is a plant survey, comprising an inventory of equipment sizes and operating parameters during the steady state survey period. Typically, mill loads and power drafts, cyclone flows and pressures, ore tonnages and pulp densities are measured. All process streams are sampled and accurate size analyses are determined. Bond work indices and breakage parameters are determined on the new mill feed sample. The optimised milling conditions are then fed into the simulation and the effects on the cyclones are assessed to ensure correct operation. Other simulations then examine subsidiary effects such as grate size, recycle crusher treating part of the mill load, and the effect of a finer crush size on the mill feed rate.

Sustainable process design for eco-comminution® circuits

Validated JKMRC HPGR modelling provides the ability to assess the power required in the grinding circuit. It then translates the power requirement into a range of options for HPGR selection and HPGR dimensions. After selecting a HPGR, the performance expected from the unit can be evaluated under a range of conditions such as changes to grinding force, rolls speed or rolls surface geometry. An appropriate motor size can then be recommended. If pilot plant data is available, JKSimMet is utilised to build a closed circuit model of the selected circuit. Pilot plant and predicted data from the model are then used as the basis for an engineering design brief. JKSimMet is particularly useful in assessing the transfer size from HPGR to ball mill or from SAG to ball mill.

Hence, complete circuits can be specified including SAG or autogenous mills, ball mills, screens and cyclones. Advice on the selection of mill liner type, profile and material can also be presented, tailored to the particular mills selected.