Kissed by the sun and clouds: Beautiful central Madeira, with the road disappearing into the Ecumeada Tunnel.

AN ISLAND OF TUNNELS

Focus on a booming business in Madeira

On the volcanic island of Madeira, located in the Atlantic Ocean 545 kilometres from the coast of north Africa, mountains plunge from 1,800 metres into deep valleys. Roads are tortuous and often dangerous - which is why tunnelling is a booming business.

Travelling the old roads of the beautiful Portuguese island of Madeira is fraught with problems. Inland routes are slow and winding and steep cliffs tower over the oceanside roads, bringing rock falls caused by floods from the mountains in winter.

The answer to these problems has proved to be tunnelling and the Via Rapida road from the airport to the capital Funchal is a typical example. Most of it runs over bridges and through 22 tunnels - with a further six to be constructed - and the efficiency and beauty of the route is a tribute to the expertise of the contractors.

Atlas Copco's tunnelling equipment is in frequent use on the island and two Boomer drill rigs, a 104 and a 135, will be used on the new Via Rapida tunnels by three contractors - Zagope, Tamega and Avelino Farinha & Agrela.

A total of 11 Boomer rigs are being used on nine current tunnelling projects in Madeira and Atlas Copco Swellex rock bolts are also a favourite reinforcement method in the typical volcanic basalt and tuff mix of rock.

Tecnorocha President António dos Santos Lopes: His company has built 40 tunnels in Madeira.

Mining & Construction reports on three of the ongoing projects, all of them progressing according to schedule with the help of Atlas Copco equipment and expertise.

Dangerous route

The Porto Moniz project near São Vicente consists of five tunnels up to 1,269 metres long. From the end of 1999, it will divert heavy traffic from the scenic coastal road that runs under the cliffs by the ocean - a dangerous route because of rock falls and floods.

The Portuguese contractor Tecnorocha is using three of their fleet of nine Atlas Copco Boomer drill rigs equipped with COP 1238 rock drills - a Boomer 281, a 132 and a 170. Blastholes are 4.2 m deep and the advance varies between 3.5 and 4 m per blast, resulting in 7 m per 24 hours.

Standard Swellex rock bolts, together with mesh and shotcrete, provide permanent support and Engineer Miguel Gouveia says: "We use Swellex bolts because they have proved to be the most cost-effective solution. They enable us to finish our project sooner and utilize our equipment more efficiently."

Miguel Gouveia on the Porto Moniz project: "Swellex bolts are the most cost-effective solution."

The Ecumeada Tunnel, being built through the Serra de Agua mountain in the centre of the island, will be 3.1 km long when it opens in November, 2000. It will be Portugal's longest tunnel and is expected to cut driving time from the north to the south coast by 20 minutes - and make it a much safer journey.

Contractor EPOS is tunnelling by drill and blast, using Standard Swellex rock bolts together with steel fibre reinforced shotcrete when the rock is good enough and steel arches together with wire mesh and shotcrete when it is not.

The volcanic rock formations can change very quickly and heavy water inflows are often experienced. Says Geotechnical Engineer Luis Santos: "Swellex bolts are very quick and easy to install and, in these constantly-changing conditions, they give a very good anchoring effect."

Water inflows

Ponta do Sol is a project which consists of three road tunnels with a total length of 1,900 metres. Today, the road runs close to the ocean through old tunnels with smaller cross-sections than the 66 m2 designated for most new tunnels on the island. A recent 4,000 m3 rock fall stopped construction temporarily - fortunately, without injuries.

Bolting performance with the Boomer 352: Fifteen bolts per hour with the pneumatic Swellex pump and up to 30 bolts per hour with the hydraulic pump.

Avelino Farinha & Agrela are using an Atlas Copco Boomer 352 for drilling the blast and bolt holes and very large water inflows are being dealt with by rock reinforcement involving Swellex rock bolts and wire mesh and shotcrete, followed by the application of a waterproof plastic sheet before the final 25 cm-thick, cast-in-place lining is made.

The heads of all bolts are cut away to get an even surface before the plastic sheet is installed.

Mountains that made Madeira

The chain of mountain peaks that form the Madeira Islands - an autonomous region with its own government - rise some 5,300 metres from the bed of the Atlantic Ocean.

Madeira is the largest island of the archipelago and is 57 kilometres long and 22 kilometres wide. It has a population of around 260,000, of whom 120,000 live in the capital, Funchal.

The sister island of Porto Santo, with some 5,000 permanent residents, lies 42 kilometres northeast of Madeira and to the south are the Desertas and Selvagens island groups, which have no fresh water and are uninhabited.

Madeira is a popular holiday resort and is noted for its rich and heavy wine, which is fortified with brandy. Agriculture, fishing and handicrafts are important parts of the economy and bananas and sugar are major exports.