China, the world’s biggest consumer of copper, cut imports of the refined metal to the lowest level in 18 months in August as domestic production climbed amid increasing foreign purchases of ore and concentrate. Inbound shipments of refined metal slumped for a fifth month to 232,066 metric tons from 251,235 tons in July and 262,691 tons a year earlier, according to the customs administration on Thursday. Refined-metal exports jumped more than four-fold from a year earlier. Ore and concentrate imports were 1.45 million tons in August, the biggest in six months and 26 percent higher on year, according to data released earlier. The purchases included 407,451 tons from Peru and 366,772 tons from Chile, compared with 223,209 tons and 392,723 tons respectively a year earlier. Chinese smelters ramped up production to the highest level in at least six months in August as profit margins rose, reducing the need for refined-metal imports. Overseas purchases of concentrate and ore have surged 34 percent this year as smelters expand capacity and treatment fees increase. Purchases of refined metal were still 16 percent higher in the first eight months from a year earlier, the data showed, after record shipments in the first half on the back of a credit boom and property rebound. Outbound refined cargoes were 57,260 tons last month from 75,007 tons in July and 12,890 tons a year earlier, and they more than doubled in the first eight months to 335,317 tons.