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Taiwan quarry gets the Coprod experience
The Taiwanese town of Hualien, is world renowned for its vibrant marble industry. But when it comes to advanced drilling technology, it is the town's limestone quarries that are setting the pace. The
Ho Ping limestone quarry in Taiwan has boosted productivity and environmental
standards with the help of state-of-the-art surface drilling technology.
Over the
years, Chien-Kuo has evolved from mining with manual labour to the use
of highly mechanized equipment and environmentally-friendly methods.
Unique challenge The Ho Ping quarry has been in operation since 1981 and is the largest limestone quarry in the country. It is worked using bench drilling from the top of the Ho Ping hill and is designed to keep noise and vibration to an absolute minimum while maintaining maximum visibility on the site. This is especially important in winter - at its altitude of 900 metres - where the entire area is often shrouded in mist and can be damp and cold, all of which reduces working hours and safety. To reduce the noise, dust and danger caused by truck movements, the rock is fed down a system of shafts to rotary impact crushers, and transported to a storage facility at the bottom of the hill by conveyors running through a system of tunnels.
There are three major vertical shafts, 6-m in diameter. The first, 900 m-long tunnel went into operation in 1981, the second, 1,100 m-long, began operation in 1986 and work on the third, which will be some 600 m-long, is currently in progress. Previously, Chien-Kuo used five drill rigs from three competing manufacturers to drill 89 mm holes to a depth of 11 m on a 3.2 m x 6 m-wide grid. Today it has a production fleet consisting of six Atlas Copco ROC F9 CR rigs equipped with the Coprod system. The rigs are drilling 127 mm holes up to 30 m deep - a performance which, according to the contractor, other machines cannot achieve in such fractured rock. Furthermore, a bench height of 30 m is also regarded as a record in the Taiwan cement quarry industry. Explains Mr Ho Chun-Loi, Deputy Manager for Chien-Kuo Construction: "The powerful ROC F9 CR rigs are proving to be highly productive compared to their predecessors here at Hualien. The rigs are particularly well suited to the quarry's loose and fractured rock. The gross penetration rate is also much faster, with a maximum output of 25 m/h compared to 12 m/h with the previous rigs. We are more than satisfied with the results." Chien Kuo carries out two blasts per day, 28 days a month. The drillers are currently drilling 105 mm holes which compare favourably to the 89-102 mm holes drilled by the company's previous machines.
Straight hole benefits The Coprod system used with the ROC F9 CR rigs makes it considerably easier to drill straight holes, enhancing productivity and performance in quarrying work. The system features a drillstring that employs impact rods to transmit impact energy and feed force while rotational torque and flushing are transmitted by drill pipes. Now, with the latest technology in hand, Chien-Kuo expects to increase Ho Ping's production by approximately 20 percent, from one million tonnes per month in 2000. An Atlas Copco service team spent a month on the site, monitoring machine performance, training rig operators and observing the operation to tackle any potential problems. In addition, Chien-Kuo is maintaining an ample stock of parts and consumables to cope with the increasing production rate.
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