Doupling the production capacity of a Spanish quarry to 800 tons per hour

The new, stationary plant is now able to produce all high-quality aggregates grades required by regional customers like ADIF, the administrator of Spanish railways. The quarry products include railway ballast, asphalt and concrete grades, and manufactured sand.

Ofitas of Santutis belongs to the Ajuria family, second-generation quarry owners who thoroughly know the world of stones. The family also owns the quarries of Ofitas de San Felices in the Rioja region, and Ofitas del Marquesado in Granada, both built with Metso equipment.

Modern, automated plant that is easy to adjust

The new Ofitas de Santutis plant, designed by Metso Spain, combines new Metso equipment with the company's existing machine fleet.

"The setup is a fully automated plant, but the secondary and tertiary crushing stages can be flexibly adjusted, depending on the need, always giving end products with the same granular sizes," says Eduardo Diaz, Metso's Director of Engineering and Service in Spain.

"The customer is especially satisfied with the power solution. The plant is fed by two different generators, each feeding one section of the plant; this way, the whole plant doesn't get stopped because of a failure," concludes Diaz.

A long project to execute

"The quarry project has been long and laborious. We applied for the exploitation permits already 15 years ago. At first, only mobile equipment could be used. After 13 years, we were authorized to build a complete, stationary crushing and screening plant," says Iñigo Ajuria, Managing Director of Santutis de Ofitas.

The quarry has known ophite rock material reserves of more than 10 million tons with a Los Angeles value of between 9 and 11; this makes it top-quality material for the production of ballast for the Spanish high-speed trains.

Mobile primary, stationary secondary and tertiary stages

The 0-900 mm fraction from the quarry face is first separated in a feeder, classifying the 0-40 mm fraction (called sterile) onto the soil before primary crushing.

After scalping, the 40-900 mm fractions are fed to the Metso Lokotrack LT125 mobile jaw crushing plant, which reduces it to a size of 0-200 mm, and collected in a stockpile.

Secondary crushing is handled with a Metso Nordberg HP4 cone crusher, equipped with an extra coarse crushing chamber.

"The HP4 cone, weighing about 24 tons and operated with a 315-kW motor, is probably the world's best cone crusher for manufacturing railway ballast," says Angel Luis Garcia del Val, Commercial Director of Metso Spain.

The output from the HP4 is sized 0-80 mm and screened with a Metso Premier CVB2060-3 inclined screen to four different sizes: 0-5, 5-30, 30-63 and >63 mm.

Fine crushing is carried out with another HP4 cone crusher, equipped with a fine crushing chamber. Depending on the demand for the different fractions, the HP4 can be operated as a secondary or tertiary crusher.

At the second screening stage, the 0-25 mm fraction from the HP4 is screened further with a Metso Premier CVB 2060-4 screen to five different sizes: 0-5, 6-12, 12-20, 20-25 and >25 mm.

A unique plant configuration

The new complete plant has two main differences compared to conventional plants. Here, the mobile primary crusher is installed at the front of the quarry, feeding into two cones and two screening sections.

The plant also houses two independent feed hopper lines, so it can be configured to operate with cone crushers working as secondary or tertiary crushers, depending on the end product sizes needed. This makes it possible to double the plant capacity to 800 t/h.

"Ofitas de Santutis represents a modern, next-generation plant with very innovative, multi-functional and flexible configurations. Actually, it's a perfect example of Metso's plant design," concludes Angel Luis Garcia del Val.

The story is based on the original text and photos taken by Luis Fueyo of Rocas y Minerals magazine.