Riversdale acquired 74% of the underground anthracite mine in South Africa in December 2005 with its Black Economic Empowerment (BEE) partner, the Maweni Mining Consortium.
It increased ROM coal by 8% to 799,196 tonnes and sales by 56% to 785,995t in the 2007 financial year when compared with the previous annual figures, accredited to improved mine and processing equipment and contribution from the Deep E section that came online midyear.
The Deep E block, or Kwa-Sheleza reserves, development is expected to increase the mine's life by 15 years and add an initial base production of 24,000t per month to production.
ZAC's production mix includes a continuous miner section (14,000tpm), three conventional sections (24,000tpm) and four shortwall sections (13,000tpm).
Since taking over ZAC Riversdale has invested $9.5 million on plant and equipment, $6.2 million on exploration activities and a further $3 million on tenement acquisitions in Mozambique.
Riversdale will focus on exploration of tenements of its site in the Moatize Coal Province, which is considered to be one of the largest underdeveloped coking and thermal coal provinces in the world.
Other financial results included an operating cash flow of $18.2 million, up on the previous year's $2.3 million, due in part to the sale of ZAC coal stockpiles and improved operational performance.
"This is a good result for the company in a year in which we acquired the Mozambique tenements," said chairman and CEO Michael O'Keeffe.
"With our strong cash position and ongoing contribution from ZAC, we are well positioned to continue the growth of the company."
The directors did not declare a dividend for the year.