Home Insights Case studies Aggregates Use of electricity results in efficiency and savings at Erkko Näppi Oy crushing and screening plant
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Feb 20, 2017

Use of electricity results in efficiency and savings at Erkko Näppi Oy crushing and screening plant

When crushing contractor Erkko Näppi Oy crushes and screens at the Rikantila quarry in the Finnish municipality of Eurajoki, of the company’s crucial machinery, only four wheel loaders and one excavator need refueling. The entire Metso three-stage crushing chain and double-deck screen run efficiently and cost-effectively with electricity
ES402 Metso Outotec screen. Double-deck screen.
The new Metso ES402 double-deck screen efficiently handles feed from the secondary crusher and overflow from the tertiary crusher.

“As we’re always operating at the same quarry, fixed electric crushing and screening is the best solution. For us, electricity is significantly more efficient and cost-effective. Considerably less maintenance work needs to be done compared with the corresponding diesel-operated equipment,” says managing director Teijo Näppi.

“We have relied on Metso equipment since the Lokomo 50 Series jaw crusher. With a local manufacturer, spare parts and maintenance services are close. The Metso equipment has kept solid and advanced in their field,” he adds.

More than 20% more efficiency with GP330 gyratory crusher and ES402 screen

Erkko Näppi started his career as an entrepreneur as a truck driver in the 1960s. During the following decade, the business expanded into gravel hauling and later into crushing. At the turn of the millennium, the new generation took up the reins.

Over the years, the company has constantly renewed their machinery. The most recent investments have been a Metso Nordberg GP330 tertiary crusher, PREMIER ES402 double-deck screen and six new cassette trucks. Also among the new acquisitions are four Volvo wheel loaders.

“By replacing the gyratory crusher, we increased efficiency by more than 20% compared to the GP300 model. With the GP330 installed last summer we have achieved capacities of even 600 to 700 metric tons per hour. For example, we can produce the 0–16 mm grade at a regular capacity of more than 400 metric tons per hour. We use the 22-mm setting and the 36-mm stroke in the gyratory crusher.”

“An additional benefit of the new gyratory crusher is that it produces excellent aggregate in terms of shape, and extends the mantles’ service life by 20,000 metric tons,” Teijo Näppi adds.

General manager Teijo Näppi (left) and production manager Henri Järvinen monitor the figures of the PA adjusting system for the crushing plant, which enhances efficiency and consistency.
General manager Teijo Näppi (left) and production manager Henri Järvinen monitor the figures of the PA adjusting system for the crushing plant, which enhances efficiency and consistency.

From the Metso C125 jaw crusher, the aggregate moves on to the GP300S secondary cone crusher, and from there to the new ES402 screen that has considerably increased screening capacity.

“The screening surface in the new ES series screen has increased from 12 to 15 square meters for each deck, and at the same time, capacity has increased from 300 to more than 400 metric tons per hour. We use Metso rubber mesh on the upper deck and steel mesh on the lower one.”

“Another benefit of the large ES screen is the ease of replacing the meshes. There is enough space even for a big man to operate.”

Moreover, replacing the wear liners of the C125 jaw and GP crushers is a quick operation (it takes 3 to 4 hours), because there is free space for lifting above the elements.

At Erkko Näppi Oy, basic maintenance, such as replacing wear liners, is done by themselves. For specialized tasks and technical guidance, they rely on Metso experts’ assistance.

The PA adjusting system controls and regulates production

All the crushers are connected by a sensor to the Metso PA adjusting system for crushing plant, whose brain and screen have been conveniently placed inside a protective steel container. Wireless cameras transmit real-time images of the crusher’s gaps to the wheel loader’s cabin.

The recipes for several different grades can also be saved in the PA system, which makes it faster to adjust the crusher.

“Production stability and quality are the number one priority for us. We crush for 8 to 10 hours daily, which is why it’s important that high-quality material comes from the conveyor evenly and without interruptions.

Cassette trucks fetch different aggregates from the Rikantila quarry at a steady pace and take them all over the Satakunta region, even all the way to Turku.  Erkko Näppi Oy produces a wide variety of crushed stone that caters for every need: more than 10 zero-based grades and seven cut gravel products.

The Rikantila stone is used to make asphalt and concrete varieties, as well as construction and road foundation material. The company offers industrial sand made from crushed stone, as well as traditional red natural sand if required.

 

Metso and Outotec merged into one company on July 1, 2020. This case study was written prior to the merger

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