Metso equips new Al Dhahira quarry
The new Al Dhahira Tarmac quarry in Oman has been fully equipped by Sweden's Metso and is set to be a major supplier of sand and aggregates to not only Oman and UAE but also other Gulf states.
01 September 2002
Swedish company Metso Minerals has fully equipped Tarmac's new quarry at Al Dhahira in Oman with crushing and screening equipment on a turnkey basis.
The Al Dhahira Tarmac quarry is the largest wadi gravel deposit Tarmac has overseas.
Designed to have a production rate of 650 tonnes per hour, the equipment consists of a primary C100 jaw crusher, three NP11-10 impactors, one HP200 cone crusher, five 12 sq m screens and in excess of 40 conveyors.
Located close to the Oman-UAE border, the Al Dhahira site covers an area of approximately 40 sq km and has already been earmarked for further expansion.
The site replaces an older nearby ABC Tarmac quarry and will supply high-quality crushed sand, natural sand and aggregates to the UAE market as well as further afield.
"There is a construction boom in Dubai and Abu Dhabi, and consequently demand for our products is increasing. This new quarry with its 3.3 million tonnes a year production will go a long way to supplying that need," says site general manager Dave Thomas.
Due to environmental concerns, Kuwait and Bahrain have closed down all crushing and screening operations, with Qatar soon to follow suit. Consequently quarries such as Al Dhahira are poised not just to supply Oman and the UAE, but the entire Gulf region.
The recently-installed Metso Minerals equipment consists of primary, secondary and tertiary crushing and screening equipment.
The primary circuit is a single C100 single toggle jaw crusher with a feed opening of 750 mm by 1,000 mm. The material is then fed to the three NP11-10 horizontal impactors to produce three different products: asphalt, ready mix and sand.
Material is fed to the primary crushers via a push feeder and a two-deck vibrating grizzly, with undersized material passing through one of the site's CVB 2060 2m by 6m triple screens.
Each of the impactors feeds onto a dedicated CVB2060 triple deck screen to classify and check for the correct product size and cubicity. The site's processing plant also includes one HP200 cone crusher for sand production.
To meet stringent pollution regulations, the plant also incorporates a dust suppression system which includes infrared-triggered spray systems at the feed points.
According to Thomas, the Metso equipment was chosen for this particular quarry because of the company's ability to deliver equipment capable of producing products at exact size and quality.
This area is also close to the water table, with nearby water bottling plants supplying Oman and the UAE. Any pollution or dust from the site is strictly controlled.
"Metso also guaranteed that there would be minimal dust and pollution from the site which was of utmost importance along with excellent back-up," says Thomas.
"The equipment is environmentally friendly with dust suppression and extraction meeting the strictest Omani regulations."
The quarry will produce aggregates to standard sizes including, 40/25 mm, 25/20 mm, 20/10 mm, 10/5 mm, 5/3 mm and 0/3 mm, while natural sand will be produced in three sizes 20/10 mm, 10/5 mm and 0/5 mm. The site anticipates that of the 3.3 million tonnes a year produced, 1.6 million tonnes will be crushed material.
The quarry has the potential for at least 20 years production and is Tarmac's largest wadi gravel deposit in the region. The rock extracted from the site is limestone and very hard gabbro; the latter will supply the company's asphalt plants in Al Ain and Abu Dhabi.
Work on the site initially commenced in August 2001 with the first earthmoving. By December 2001 the first Metso equipment was being delivered via Muscat, and erection was completed in May 2002.
To power the plant, the site has been connected via overhead electricity cables to a mains sub-station 4.5 km away at Wadi Sa, Oman. These cables took six months to complete, and cross an inhospitable and desolate landscape.
To cater for equipment breakdown or power cuts, the site will maintain stockpiles of 150,000 tonnes, enough supplies for at least two weeks.
"With Metso's excellent back-up and resources, there is no reason to think that any piece of equipment would take longer than that to be fixed," says Thomas.
The quarry has a full complement of 100 staff, that are divided into two shifts each working 10 hours a day six days a week. Most of the workers live on-site, where Tarmac has constructed a purpose-built camp equipped with essential amenities.
The site also has three automated load out facilities, sourced from Metso, and twin weighbridges, to expedite truck movements.
The new quarry is around 40 km from the nearest town. At present, Tarmac is constructing a 14 km-long asphalt access road, which will connect to the nearby main highway to the UAE border and Al Ain.
Metso Minerals, part of Sweden's Metso Corporation, is a global market leader in the rock and minerals processing industry. The company focuses on the supply and service of processes and related equipment.
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