South African valves manufacturer Atval has successfully manufactured and delivered three 800 mm pinch valves to gold mining major AngloGold Ashanti’s Siguiri mine, in Guinea, West Africa, and is seeking to expand its operations in Africa.

The valves were delivered to site last year, enabling the project to increase production from 9-million tons a year to 12-million tons a year.

However, Atval owner Ted Atkins tells Mining Weekly that the valves have not been commissioned yet and, according to the mine’s engineers, the valves will be commissioned only in the third quarter of 2013.

The company is currently also involved in several projects in Zimbabwe and Botswana.

“Atval attended the third yearly Zambia International Mining and Energy Conference and Exhibition in June, where it made important contacts,” he enthuses, adding that the com-pany also intends to attend future mining-related conferences and exhibitions in Africa.

The Siguiri mine is AngloGold Ashanti’s only operation in Guinea; government has a 15% stake in the mine and the balance is held by AngloGold Ashanti.

Atkins notes that the project was completed in four months and comprised the design, tooling, manufacturing and testing of the valves.

“The 800 mm nominal bore 10 bar KE series pinch valves, with enclosed body design, were fitted with B-grade heavy- duty natural rubber sleeves. The valves were installed on the ring main at the Siguiri gold plant’s tailings facility, where Anglo-Gold Ashanti increased its pipeline from 700 mm to 800 mm in diameter to accommodate the increase in production,” he explains.

Meanwhile, Atval director Mark Atkins notes that pinch valves were used in this application owing to their longevity in high-wear applications.

“The valves were fitted with double-acting hydraulic cylinders, which were manually actuated by hydraulic hand- pumps that were welded to the side of the valves.”

Mark Atkins highlights the fact that the requirement for pinch valves in South Africa is rarely larger than 500 mm.

“Larger valves are generally used in applications where there are low yields of precious metals in the rock. We had previous experience in manufacturing an 800 mm valve, which was used to assist in distributing water in the Lowveld of Mpumalanga. The expertise gained from that project helped us to successfully complete the AngloGold Ashanti project,” states Mark Atkins.

He says the company also supplied a 700-mm-dia- meter pinch valve to mining company Debswana in December 2012 for use on one of its diamond mines, in Botswana. Atval also supplied four 600-mm- diameter valves to a mineral processing facility, in Maur-itius, in July 2012.

He says this is an advantage that Atval has over its competitors, as it can react quickly to requ- ests for new designs for valves not previously manufactured.

He says these quick resp- onses are supported by a well-proven design formula and design calculations, as required by the company’s ISO 9001:2008 certification.

“This is what ultimately contributed to Atval being chosen by AngloGold Ashanti for its Siguiri project,” advances Mark Atkins.

Challenges

According to Ted Atkins, Atval had to manufacture all the tooling required for the production of the valves. Once the tooling was completed, in-house machinery had to be built to handle the manufacturing process.
He adds that special machinery had to be manufactured for the manufacturing of the pinch valve liner.

“Testing the valves also proved challenging, as all pinch valves require standard proof testing of the sleeve to three times the working pressure. We had to upgrade our testing facilities to accommodate the sheer volume of water required to do the testing,” Atkins explains.

Other testing was also required in the manufacturing of these valves, which included a full mechanical test, a standard closure test against 110% of line pressure and a standard sleeve test at 200% above working line pressure.
“All these tests were con- ducted according to Atval’s quality procedures and in accordance with ISO 9001:2008,” he stresses.

Atkins adds that the company’s plant is built to handle the manufacture of valves up to 1 000 mm in diameter and its technology can manufacture large sizes.

Despite several serious challenges faced by the South African valves market, such as labour unrest in the mining sector and overall energy price hikes, Mark Atkins points out that the Department of Trade and Industry (DTI) formally announced in January the further designation of valves, manual and pneumatic actuators and electrical and telecommunication cables, as well as components of solar water heaters, for local production and content in the public-sector procurement system.

Trade and Industry Minister Dr Rob Davies signed the necessary authorisation in terms of his powers under the Amended Regulations of the Preferential Procurement Policy Finance Act (PPPFA) in March.

Public procurement is one of the key industrial levers in the Industrial Policy Action Plan. The revised PPPFA regulations, which came into effect in December 2011, empower the Minister of Trade and Industry to designate industries, sectors and subsectors for local procurement at specified levels of local content.

The designation policy instru- ment is one of a suite of policy levers designed to maximise sup- port for domestic manufact- uring. The others are the Com-petitive Supplier Development Programme – which is led by the Department of Public Enterprises and governs the pro- curement programmes of State-owned companies – and the National Industrial Participation Programme.

This instrument obliges overseas companies, which have won tenders worth more than $10-million, to provide offset obligations through investments in the domestic economy.

Mark Atkins highlights Atval’s close involvement with the DTI over the past 18 months regarding this initiative through a cluster initiative of the Valve and Actuator Manufacturers’ Cluster of South Africa, which is a member of the South African Capital Equipment Export Council.

“This initiative will help create employment and develop the valves and associated industries as well as assist industries further down the supply chain, especially the foundry industry. Therefore, Atval aims to target State owned enterprises, such as those invol-ved in water and power generation, more aggressively in the near future,” he concludes.