JAKARTA, July 20 -- Indonesia's refined tin exports fell 7.3 percent in June from a year ago as easily mined tin resources have been depleted, the trade ministry said on Monday.

Indonesia exported 8,029.92 tonnes of tin -- which is used in soldering electronic goods and for food packaging -- in June, down from 8,661.2 tonnes a year ago, trade ministry data showed.

"Exports fell because tin resources in onshore mines have been depleted, cutting production," said an official at the trade ministry, who declined to be quoted by name.

"Based on technology and financial capability, only PT Timah and PT Koba Tin are able to explore offshore mining," the official said.

State miner PT Timah Tbk (TINS.JK: Quote), the world's largest integrated tin miner, has invested in building dredges so that it can mine offshore as the more easily mined onshore reserves are gradually depleted.

Exports may pick up in the second half of the year during the dry season, but the depletion of tin reserves means that exports are still likely to be lower than in previous years, a physical trader in Singapore said.

"We have come to a period where easily recoverable high-grade tin reserves have gone," the trader said.

"Refinery capacity has not been the issue, it's the concentrate supply that will set the tone."

About 85 percent of the cargoes in June were shipped to Singapore, while the remainder was shipped to Malaysia, the Netherlands, Japan, Taiwan, the United States, China, South Korea, India and Turkey.

Refined tin exports in the January-June period was estimated at 43,263.47 tonnes, down 14.5 percent from 50,575.2 tonnes in the first six months of 2009, data showed.

The tin industry in Bangka-Belitung, off Sumatra, has been hit in the past four years by weaker tin prices, a police crackdown on illegal mining, and the depletion of easily mined onshore reserves.

Tin for three-month delivery CMSN3 on the London Metal Exchange stood at $17,700 a tonne on Monday, gaining 4.42 percent so far this year.