SHANGHAI, Jan 20 (SMM) -Copper inventories in the domestic bonded zone grew 16,400 mt from January 13 to 87,200 mt as of January 20, according to SMM survey. The inventory in the Guangdong bonded zone dipped 300 mt to 5,300 mt WoW, which was contributed by the low arrivals, while that in Shanghai added 16,700 mt to 81,900 mt WoW. The SHFE/LME copper price ratio dropped again this week. The import losses once surged to more than 1,600 mt over the SHFE front-month copper, which greatly suppressed the market demand. Bills of lading arriving at ports were generally moved into the warehouses. Goods for exports shipped by some domestic smelters will also be stored in the bonded zone warehouses first amid the open export window, which will push up the bonded zone inventory rapidly.