To open up new alternative revenue streams, a Namibian marble operation decided to crush rejected marble slabs as a value-add to its business. Materials produced out of the waste comprise 0-1mm for various industrial uses, as well as 1-6mm, 6-15mm and 15-40mm for general aggregate.
“While well entrenched in the market, with a product ranked among the top quality-wise, there were two options to grow the business. They could either produce more marble, which was undesirable as that would compromise the lifespan of the quarry, or they could use waste material that continuously piles up on site. A decision was made to crush waste material into a valuable product,” explains Fernando Abelho, Africa sales manager at Pilot Crushtec. The newly crushed waste material has a number of uses in the construction and industrial sectors, from tile grout to additives in commercial products – basically anywhere a fine powder is required. Previously, the operation ran a Metso mobile jaw crusher and screen. However, with the old single-stage crushing set-up, it experienced high inefficiencies, which resulted in re-handling of material, translating into high cost of production per tonne.
“Initially, they were using a jaw crusher and screen to do single-stage crushing, but were achieving very low volumes,” explains Abelho. “The team from Pilot Crushtec spent about six months with the client in order to understand their business. The client did an exhaustive analysis in terms of what other industrial uses there could be for its waste and what specifications were required to compete in that market. Pilot Crushtec was then consulted on how to achieve the required product specifications.”
Pilot Crushtec’s initial idea was to just put in a screening plant to reduce double-handling of material, thus dropping operating costs. Essentially, this meant the material was fed into the jaw crusher, split into three usable products, and a fourth product that was still too large to be of any use had to be reprocessed.
The extra screen, however, would not solve the problem as the client’s production rates were just too low and the cost could not be justified. The only logical solution was to increase production, and the Rubble Master RM 90GO! impact crusher was deemed to be the perfect tool for the job at hand.
“The client needed a reliable crusher that could increase production significantly, provide flexibility in terms of product specifications and produce a high percentage of fines (due to the relatively small demand for aggregate products in the region),” says Abelho.
Capital costs of the equipment were a major concern as the concept was to beneficiate a waste product. While a secondary cone crusher could offer those benefits in the correct application, an impact crusher was considered a much superior solution for this project considering that the feed material is non-abrasive.
“Impact crushers offer much higher reduction ratios than cone crushers, and with variable speeds and crusher gaps, you have significant control over final product curves. From a maintenance point of view, impact crushers are also simpler to maintain and operate than cone crushers,” he says.
“The Rubble Master has been at the forefront of compact crushing and screening for a number of decades and offers premium models that punch above their weight without compromising quality. Combined with Pilot Crushtec’s commitment to parts holding and high calibre of support technicians, the final choice was an easy one for the client,” adds Abelho.
With the Rubble Master RM 90GO! in place, there now exists a thorough two-stage crushing process. The operation’s plant now produces at a much higher volume and with less re-handling. Abelho says during commissioning the plant achieved up to 280tonnes per hour (tph) peak production, which is not sustainable over a long period of time. However, the quarry is currently operating comfortably at between 180-200tph.
“Fixed operating costs have remained relatively the same, but production has increased considerably, while the cost per tonne has been lowered significantly, meaning higher profitability. Higher production and lower costs mean they are more competitive and are able to look for more clients,” says Abelho.
Explaining the mechanics of crushing, Abelho likens the process to driving a car. “One needs to go through all their gears to get to the top speed and it is the same when crushing. You have your first stage that will generally round off the material from 600mm to about 100mm,” he says.
“The second stage will then further reduce the size from 100mm down to about 25mm. You can, of course, abuse the various stages but this does come at a cost. Your efficiency will suffer, wear and tear will increase and production levels will drop. The client has eliminated these negatives by installing a Rubble Master RM 90GO! and production has almost tripled. They are at a point where they have to find more clients for their industrial products,” adds Abelho.
The philosophy behind the design of the Rubble Master has always been simplicity in operation and maintenance without compromising on quality and performance. Pilot Crushtec often uses it to introduce clients with minimal experience to the crushing and screening industry.
“The Rubble Master is really easy to run. From a maintenance and operation perspective, there is nothing simpler. The control panel literally has four buttons that get the machine going; we call it the one, two, three, Go!. You push three buttons, and you are ready to start crushing. This is great as the learning curve for operators is very short, relative to cone crushers where countless set-up parameters are available via the PLC (Programmable Logic Control). All the intelligence is hidden within the machine,” says Abelho.
“Additionally, the size has intentionally been kept compact as it is often used in urban environments where space is at a premium. We have clients that use the Rubble Master to crush backfill when working on residential complex projects as the machine is incredibly mobile and has great sound insulation.”
The Rubble Master comes in three iterations that serve a wide variety of markets. Typically used in low-abrasion and construction and demolition (C&D) waste applications, the RM range can be used in some harder applications under correct circumstances. The starting point for any prospective client is most certainly the Rubble Master RM 70GO! 2.0 impact crusher.
The compact, track-mounted machine produces cubic-shaped grain in various product sizes and is designed to process a wide range of aggregates material. The diesel/electric drive makes this unit economic and efficient and, due to its power and versatility, the compact crusher is a vital piece of equipment for companies specialising in recycling. “If you have wider application needs and more demanding power and handling expectations, the RM 90GO! is the answer,” says Abelho.
The RM 90GO! is a low-noise, high-performance crusher suitable for an array of applications. Set-up is simple and the machine is ready for action within a few minutes to rapidly and efficiently process any material, such as C&D waste, concrete, asphalt, glass, coal, natural rock and even reinforced concrete, to produce high-quality construction materials.
Rounding off the range is the Rubble Master RM 100GO! compact crusher. The track-mounted unit produces a high-quality, cubic-shaped grain in various product sizes. Due to its power and versatility, the compact crusher offers a flexible approach to high-capacity crushing. The Rubble Master RM 100GO! is a primary or secondary crusher with a refeeding belt that sends oversize material back into the vibro-feeder and returns it to the crusher.
“Diversification and identification of alternative revenue streams are the keys to success and sustainability in the 21st century. With a variety of applications that open up with the Rubble Master range, it has never been easier to retool or upgrade when the need arises,” concludes Abelho.
