Predominantly a crushing and screening (comminution) contractor in the mining, civils construction and recycling industries, Seneca Crushing and Screening cut its teeth in demolition waste recycling, before expanding its foothold into the mining industry, with a special focus on iron ore in the Northern Cape province.
The company entrenched itself in this market and quickly became a preferred supplier to many mining houses within the iron and manganese resource areas. The processing of these ores, says Gareth Nettmann, Group Contracts Manager at Seneca, is demanding on the equipment and calls for sound management of maintenance and plant availability due to the hardness, abrasiveness and work indexes of the ores. Seneca has over the years excelled in these difficult applications.
“We have been able to deliver consistent performance on our contracts with our clients and by extension, we have been instrumental in their being able to conform to their KPIs and thus honour their offtake and logistics commitments thereby ensuring delivery of product and feasibility of the mine,” says Nettmann.
Over the years, the company has grown its order book and subsequently its fleet to execute the growing number of jobs. Despite the recent Covid-19 debacle and the current power crisis in South Africa, Seneca has experienced consistent annual growth in the past few years.
“We have a large client base within the civils construction industry and are encouraged by the uptick within this industry after a few years of dormancy. We have a large market share and substantial presence in the coal, chrome, platinum, gold and manganese mining industries and are the forerunner in the iron space, where we process in excess of 350 000 tonnes per month (tpm) of ore alone,” explains Nettmann.
In 2020, the company decided to extend its service offering to include Design, Build, Own and Operate (DBOO) and Build, Own, Operate and Transfer (BOOT) operating models, thus moving into both comminution and beneficiation spaces. The new models have been met with great interest by customers, confirms Nettmann.
By going this route, Seneca is now able to offer its clients the luxury and value of its wealth of experience, through guiding the design of the plant and process. Clients are also able to save some of their capital as Seneca finances the processing plants, allowing for cashflow flexibility for the client. These models also give clients enough room to concentrate on better understanding their resource, mining plan, logistics and overall mine management, knowing that the comminution and beneficiation processes are managed by an expert company of Seneca’s stature. In essence, the difficult and capital extensive crushing, screening and beneficiation boxes have been ticked, allowing mines to concentrate on the balance of their operations.
Since its corporate decision to increase its service offering, the company now runs five magnetic separation plants on toll treatment basis for various clients within the manganese space and will be building its first 250 tph High Density DMS separator for one of its iron ore clients in the Northern Cape in 2024.
Part of this growing plant base is the recent DBOO crushing and screening plant for an iron ore client. Supplied by Terex MPS, the plant was completed in the third quarter of 2022 and is delivering beyond expectations, says Nettmann.
Located just outside Postmasburg, the mine is notorious for some of the toughest ore in Africa. With particular site-specific requirements, Seneca needed a plant designed, engineered and built in a short timeframe to deliver a minimum of 550 tph, explains Willem du Plooy, Regional Business Development Manager –Africa, Terex MPS.
“In consultation with the experienced Seneca Crushing and Screening, Terex MPS developed a plant suited to the variable feed characteristic expected from the mine with a layout that fitted the limited footprint available on site,” says Du Plooy.
According to Nettmann, the plant was designed to manage a feed of three different iron ore run-of-mine (ROM) characteristics – detrital ore, on-grade DSO ore and sub-grade ore – all with varying minerology, particle size distribution (PSD), feed size, crushability work indices, hardness and abrasive index characteristics, as well as varying product size specifications for preparation for beneficiation.
“Consequently, we had to go for a three-stage crushing and three-stage screening plant, with screening prior to every crushing stage, all recirculated within a closed circuit. The result is an incredible plant that has benefitted from years of Seneca’s operational experience working within varied applications, coupled with a sound understanding of iron ore, as well as our experienced and motivated staff and our close relationships with OEMs such as Terex MPS,” says Nettmann.
Terex MPS plant in detail
Terex MPS is built on a very long history of crushing and screening, encompassing some of the oldest crushing names in the world, such as Cedarapids, Simplicity, Jaques, Canica and more, all available on static, modular and portable (wheeled) platforms.
At the heart of the Seneca process plant are two Terex MPS MC320 modular cone crusher stations – with a TGS320 secondary and TG320 tertiary respectively, explains Du Plooy. The TG-Series cone crusher is known for its flexibility and high production rates and is perfectly suited to application requirements at this mine. Equipped with the Terex MPS AIC control system with touch screen, both cone crushers were set up to ensure high reduction and maximise capacity to over 650 tph.
“With a wide range of crusher liner options and adjustable throws, the Terex MPS TG-Series cone crusher can be set up to meet customer requirements and optimise feed rate performance, feed size and product quality required,” says Du Plooy.
In addition, two Terex MPS triple shaft horizontal screens are deployed. With high screening efficiencies in a small footprint, the screens deliver maximum product yield. The 1 800 mm x 6 100 mm Terex MPS TSV6203 triple deck final product screen is running at about 1 000 tph in closed circuit with the Terex MPS TG320 cone crusher. Triple shaft technology allows for high G-forces, adjustable throw angles, adjustable amplitudes, adjustable input speeds and the screen box angle itself can also be adjusted, this allows us the set up the screens to precisely meet the production and product requirements.
Feeding the plant is a Terex MPS JW55 single toggle jaw crusher, mounted on a custom-built crushing station with a double deck, grizzly pre-screen to remove any contaminated or clay material from the ROM feed stockpile. Measuring 1 400 mm wide, the Terex MPS JW55 single toggle jaw crusher produces a suitable product for the TGS320 secondary cone crusher.
Terex MPS not only boasts the TG-series cone crushers, but also the TC Series range, which is known for its ability to produce high quality product with a high fines content and quality shape for road stone product. The Terex MVP boasts the best hold-down force in the industry. The Terex MPS MVP series cone crusher can produce quality products and fines content in the toughest of crushing applications.
From the smallest of projects to the largest with complex crushing, screening, washing and even DMS requirements, Terex MPS and its extensive Africa dealer network, can provide and support Mineral Processing Systems to its customer, meeting their specific requirements no matter how remote or where in Africa.
Willem du Plooy explains, “At the end of the day we need to listen to what our customers’ needs are, they do know their customers and site requirements from a business perspective and match that with the correct processing equipment for the application, product and capacity needs, but most of all, delivery of what we promised and even more. We provide solutions not just crushing and screening equipment.”
“For this project we chose Terex MPS crushing and screening equipment. With the OEM’s proven track record, coupled with Seneca’s knowledge and experience with Terex crushers and screens in iron ore, we were comfortable with our choice and have not been disappointed,” says Nettmann.
“The plant delivers in excess of 550 tph average production and with our sound preventative maintenance schedules and wear management strategies, we achieve in excess of 140 000 tpm. We are in discussions with our client to increase the monthly minimum production requirement to 160 000 tpm.”
Looking ahead, Nettmann confirms that the company is in the design phase of a crushing and screening plant for two separate contracts, one in the mining space and another in the coal industry. Leveraging close collaboration with OEMs such as Terex MPS, he is confident that growth will continue for Seneca in an industry that places a premium value on productivity and efficiency.
Best cost solution
Seneca’s processes are always targeted at the best cost solution, enabled by a strong understanding of the resource, its geology and minerology, and thus able to maximise on the resource value and the extension of the life of mine for the benefit of clients.
“Crushing and screening equipment is both capex and opex intensive. As such, Seneca, throughout its 12 years of existence, has always realised the value of building strong relationships with OEMs in the industry. Leveraging these strong relations with our OEMs and suppliers, we can manage our costs as efficiently as possible in order to remain competitive in the market, while offering a superior, professional, efficient and guaranteed service to our growing client base,” says Nettmann.
By working closely with OEMs, Seneca strives to equip its growing fleet of equipment with the very latest in crushing and screening technology. The relationship with OEMs is of paramount significance in retaining good product support, managing spares holding and availability, managing of wear parts and wear rates, as well as consideration and maximisation of capex and opex.