Caledon is listed on the Australian and London AIM stock exchanges. Its main assets are the Cook coking coal colliery and the Minyango development project in Queensland.
Caledon sold 535,000t of mostly coking coal in 2010 from Cook, which has marketable coal reserves of 47.7Mt.
The takeover by GRAM Australian subsidiary Bidco, which is by scheme of arrangement, was first signalled in November but has been awaiting final Chinese government approval.
It would "provide [GRAM] a platform for future expansion in Australia and the region," according to a statement released by Caledon.
GRAM chairman Li Jinming said: “We are delighted to announce the acquisition of Caledon, which is a significant step forward in the implementation of GRAM’s strategy of expanding its resource-focused investment activities.
“We are looking forward to working with Caledon’s management in the future and to providing the necessary investment to substantially expand production in the years ahead.”
Under the terms of the acquisition, Caledon shareholders will receive £1.12 in cash for each Caledon share. CHESS depository interest holders will receive the equivalent of £1.12 in cash in Australian dollars.
The terms of the acquisition value the existing issued share capital of Caledon at about £313.1 million.
The acquisition is conditional on shareholder and regulatory approval.
In addition, a special resolution approving the scheme and sanctioning the capital reduction must be passed by Caledon shareholders representing 75% of the votes cast at the Caledon general meeting.
Caledon managing director Mark Trevan said: “The Caledon share price has been supported by the prospect of this transaction during a time when the equities markets have been under some pressure.
“The announcement by GRAM of this recommended cash offer allows shareholders and CDI holders to now crystallise that support by way of cash.
“For our employees, GRAM’s commitment to growing the business will provide the financial resources for delivering our strategy as well as providing the opportunities that come with being part of a much larger organisation.”
In a statement to the Australian Securities Exchange on Thursday, GRAM said it had been seeking coal assets to satisfy demand for coal in Guangdong and adjacent provinces.
“Gram is attracted to Caledon's resource of coking coal, infrastructure access, rail and potential port capacity," it said.
In 2009 GRAM acquired a 19.9% interest in PanAust, an ASX-listed copper and gold mine operator for $A215 million. In 2010 it increased its holding to 20.5%.
The Cook underground coal mine produces coking and thermal coals in a ratio of approximately 4:1 coking to thermal.
Sales in 2010 were 431,000t of coking coal and 104,000t of thermal coal, for a total of 535,00t.
In the longer term, Caledon is targeting a minimum of 1Mtpa of saleable product per annum from the Cook mine.
The coal from the Cook mine is railed to the port of Gladstone for export.
Caledon has also started a feasibility study for an underground mine on the nearby Minyango deposit, which is forecast to produce about 62% coking and 38% thermal coal with a target production of 3Mtpa.
Development of this mine is dependent on the timing of the proposed new Wiggins Island Coal Export Terminal next to the existing port facilities at Gladstone.
Caledon is a foundation shareholder in WICET and was allocated 4Mtpa of the initial 27Mtpa of export capacity scheduled for completion in 2014.
Caledon incurred a loss after tax of $11.8 million for the year ended December 31, 2010 on revenues of $93 million.
This included $7.5 million in finance expenses and a $3.5 million charge against the carrying value of the Caledon Loan Notes.