What do operators of crushers and screens look for in a machine? And what features do new-gen models possess? While the must-have features of a crushing and screening unit depend on the specific needs and goals of the operation, Nachimuthu Krishnamurthy, Vice President - Operations, Transworld Garnet India, highlights the top desirables as best-in-class efficiency, robustness and automation; versatility; and easy maintenance, durable components and effective monitoring. “Only then can you maximise the unit’s throughput and output, reduce the processing cost per tonne and improve profitability irrespective of the material handled, aggregates, minerals or recycled materials.” Drilling down to the application, some industry-specific features come to the fore. For example, “in the construction and aggregate industry, features like mobility, compact design and dust control systems may be critical, while in mining, heavy-duty components, automation and remote monitoring might take precedence,” he adds. “Aligning the features with the application is vital for the success of the unit.” CW asked users what features they prioritised. Crusher preferences “At Transworld Garnet India, we prioritise energy-saving, environmental safety (including compliances) and worker health and safety features of crushers and screens,” responds Krishnamurthy. “We prioritise the ability of the crusher to consistently deliver the desired size of output, which we insist on checking by a demonstration of the proposed plant,” says Purushotham Patel, Founder, Bharat Rocks and Mines. “We also evaluate the power consumption of the machine because that has a major impact on the operational cost and the cost per tonne of crushed material. The Proman model crusher we are currently using consumes at least 15-20 per cent less power than comparable models from other indigenous brands.” “We look for reliability, performance (high-speed crushing/screening) and safety in a crusher,” says Binu M, Managing Partner, Akshaya Granites. “Productivity without reliability is impossible, especially in products that are used in highly abrasive environments like a mineral processing site. In terms of features, Astec-Telsmith’s cone crushers have a patented overload protection design that limits the amount of force the machine needs to absorb when it encounters overloads or tramp metal, providing the best protection for internal parts and thus ensuring great uptime and minimum repair costs.” “A quick and safe chamber clearing in case of a power failure of tamp metal in the crusher saves a lot of downtime and lowers operational costs,” continues Binu. “A 44SBS crusher clears in minutes, avoiding hours of downtime. Operators simply flip a switch from the ‘crush’ mode to the ‘clear’ mode, and the upper frame is lifted vertically allowing the material to easily and safely fall through the crusher, bringing you safely back in production with a minimal loss of time and profitability. Our hydra jaw plates are interchangeable and reversible, which further reduces operational and maintenance costs. Being in an area with frequent disturbances, the hydraulic toggle avoids lesser time for restarting production after a power failure.” Also, a zero-maintenance anti-spin system includes a small hydraulic motor that is attached to the shaft, preventing the head from spinning when running with intermittent feed, adds Sunil Kumar, Managing Partner, Akshaya Granites. “No adjustments, resetting or regular maintenance schedules are needed. The anti-spin system and fixed shaft provide longer manganese life and produce a more cubical product, which makes us unique in our aggregate selling market.” “Autogenous configuration produces more spec material in a single pass,” he continues. “Reverse cascading improves the effectiveness of crushing, reduces recirculation and saves on energy. The exclusive use of anvils in the rock shelf provides a higher crushing efficiency. That’s why we prefer Astec crushers.” Screen must-haves “We look for a manufacturer who is willing to work closely with us on the entire process plan, including the steps before screening and post screening, and understands material characteristics such as flowability, bulk and particle density, particle size distribution, moisture content, temperature, material shape and the cut points to be achieved,” says Bharath Shetty, Director, Silica Mines. “Only then can screen sizing, type and design ensure success. Good design should reduce recycling loads and cross-contamination of product sizes, simultaneously focusing on optimal power consumption and minimal wear. We have found such a manufacturer in PSI Technologies Inc. It has successfully delivered high-frequency double-deck screens to our silica mines for grading 1,200 and 600-micron grades at 10 tonne/hr capacity.” “Under Swachh Bharat Abhiyan, we are using Terex Powerscreen track screens Warrior 1200 to produce fines, landfills and refuse-derived fuel,” says Manohar Kore, Managing Director, Sagar Motors, which is a municipal solid waste and legacy waste processor. “Currently, we are working for many municipal corporations in Jalandhar, Chennai, Hyderabad, Latur and Delhi. We have more than eight units working on sites. The Deutz engine is fuel-friendly, consuming just 4 litre per hour.” “We look for productivity in a screen used to make plaster sand,” says Kiran Jain, Director, Shri Dakshayani M Sand. “If we feed 150 tonne of dry sand to a machine, in the machine of our choice (Proman), we get 30 per cent more plaster sand. In other machines, we have achieved only up to 15-20 per cent more output. In the case of water sand, we get up to 70 per cent more output in a Proman machine but 15 per cent less than that in a comparable machine. This is because of the size and design of the screen and the machine.” “In a screen, we evaluate its efficiency; that is, its ability to separate oversize and undersize materials,” says Patel. “We aim for not more than 10 per cent return.” Crushing evolution Technology exchanges with other countries have helped improve the features of crushers and screens available in India. “It’s important to evaluate the underlying technology for its suitability to your application,” avers Patel. “For instance, we use vertical shaft impact (VSI) crushers from Proman to manufacture sand. These crushers are based on REMco’s reduction technology, which is undisputedly superior for the purpose. This enhances the quality of output.” In particular, the productivity and environment-friendliness of crushing and screening units have evolved significantly over the years. In that context, Krishnamurthy notes, “The features to look out for are higher efficiency ratings, durable components, versatility and mobility. Advanced automation and control systems optimise processes and reduce human intervention, leading to higher productivity. Digitalisation and data analytics allow real-time monitoring and optimisation of processes to improve productivity and minimise wastage and the environmental impact. Advances in material handling equipment and conveyors have improved the efficiency and environmental impact of the process and reduced manual labour and risk of spills or material loss.” “Environment-friendly crushing and screening units feature efficient diesel engines with cleaner technologies to reduce the consumption of fuel and minimise air pollution,” he continues. “Also, engineering and design improvements address noise pollution while innovative dust control and suppression systems reduce airborne particulate matter. A growing focus on sustainability has led to the development of crushing and screening units designed for recycling and reusing materials. Stringent environmental regulations have pushed manufacturers to design units that meet or exceed emission and safety standards.” “The recent addition of Telematics ‘powerscreen pulse’ to Terex Powerscreen track crushers and screening plants has been wonderful because we can monitor our plants from our office,” says Pralhad Deshmukh, Managing Director, PD Infraprojects, a leading NHAI contractor from Maharashtra. “This remotely operated system allows us to know the current location, crusher hours, engine hours, closed side settings (CSS) settings, wear, etc. It reduces dependency on manpower to that extent. We can also plan the wear parts. Site productivity majorly increases.” “Newer cone and jaw designs and VSI designs deliver higher productivity for a lower motor rating,” adds Jain. “We have machines with a 150 hp per hour motor rating that deliver 30 per cent more output than machines with a 200 hp per hour motor rating.” Screen updates Screening and grading technology has seen subtle changes that are producing lasting impact, according to Shetty. “Design for improved performance, reduced cost, improved durability and better safety is of significance. Previously, the tendency was to build the machine safe and heavy. Optimisation efforts weren’t based on deeper insights and could lead to costly experiments and poor deliveries. In recent years, the availability of multi-physics tools that allow designers to model parameters such as type screen, frequency of vibrations and the G force to be employed has greatly improved designs. Simulation tools strengthen the designer’s ability to put both the design and equipment to test, in a virtual but a highly reliable environment. Further, the integration of design and manufacturing is now being tackled with advancements in the CAD-CAM space.” Ghule Patil Land Developers, a company with operations in the roads and infra segments, has been using Terex Powerscreen track mobile crushing and screening plants for eight years. According to Abhijit Ghule Patil, Managing Director, the latest dual power hybrid crushers are really useful as high-speed diesel (fuel) prices are sky high. “These dual power hybrid machines are most economical,” he says. “By using grid power, we can reduce our power/fuel cost by half. Most hydraulic run motors are now electric, thereby minimising our maintenance cost. Such innovations are the need of the hour.” Astec-TelSmith’s newer products feature advanced automation and controls enabling real-time monitoring and optimisation of equipment, leading to increased productivity and efficiency. Recent innovations have enabled Astec-Telsmith high-frequency screens to operate at less than 60 per cent of the power consumption of traditional systems. “Our method of processing is environment-friendly as our system doesn’t require water or chemicals for M sand processing,” says Kumar. “It’s the best solution for silica sand processing and other minerals too. These screens also increase the use of recycled materials and recovery of precious natural resources. Certain models that are low in sound emissions are particularly of interest in urban landscapes. This high-frequency screening system is the most compact system in the industry for mineral processing. We have been honoured by a local body for our environment-friendly operations thanks to this high-frequency screening technology from Astec.” That’s ending on a high note!