Investing in new equipment and using western quarrying techniques is helping one Chinese quarry to boost productivity
Second hand machinery, combined with high demand, means that some Chinese quarries are struggling to produce continuous supplies of aggregates for the construction market.
Hong Kong owned Wah Tong Machinery Trading is working to overcome the supply problems in its Guangzhou quarry by investing in new equipment. The company is one of a new breed of contractors in the country, which are going against convention in China and using western bench extraction to maximise production.
Wah Tong has been working at the granite quarry under licence from the Chinese Government for the last 10 years and the workings are now 200m below ground level. According to the company's managing director Thomson Tan, the quarry's annual production is currently around 2 million tonnes.
"In China there is a proliferation of second hand equipment but maintenance for this equipment is minimal," he said. "Suppliers don't usually provide service back up and in China the concept of continuous service and maintenance for drilling equipment is not established yet. Productivity usually suffers because of this." "We chose to invest in two new
The two Titon 500 crawler rigs were delivered to Wah Tong's Hong Kong office and then taken by truck into China via Shenzhen to Guangzhou, which is about a two and a half hour drive from the Hong Kong border.
Wah Tong's Titon rigs are fitted with Sandvik Mission 50 down the hole hammers and Sandvik bits, which the company grinds on site to maintain performance. The rigs are used to drill 152mm diameter holes to depths of around 15m, with a 4m spacing. According to Tan, the rigs usually achieve a penetration rate of around 1m per minute.
Blasting at the quarry is carried out twice a day - once at lunchtime and again at 5pm - and is usually done simultaneously at three locations within the quarry. The blasting is designed to break the rock into pieces about 0.5m across, which are either sold without further processing for rock armour on coastal defence projects, or sent to the on site crushing plant. Crushed material produced at the site is generally in the 1 to 4mm size range.
The quarry is close to the banks of the Pearl River and both unprocessed and crushed rock is transported from the site by a fleet of barges to other parts of China or to Macau. "There is a real boom in construction on Macau at the moment which is generating a huge demand for rock and aggregate," said Tan. Crushed material is also transported to local customers by truck.
According to Tan, the new rigs have not only improved the efficiency of the quarry but are also helping the company to meet new environmental legislation in China. "The Guangzhou authorities have imposed strict new regulations concerning dust and noise on quarrying in the region," said Tan. "When you look at the productivity requirements from the market and the authorities' emission laws, the range of options in terms of equipment becomes much narrower and will increase the use of new equipment." Officially ownership of the new rigs is held in Hong Kong, which allows Wah Tong's Guangzhou operation to take advantage of the service back up of Sandvik's Hong Kong office. Tan said that the transport between Hong Kong and China has improved considerably and parts for the rigs can be easily transported by road or river.
