(Adds details, background)
RIYADH Oct 10 (Reuters) - Saudi Arabian Mining Co (Maaden) reported a forecast-beating third-quarter profit on Wednesday, helped mainly by higher prices of its core products and the start up of big new production lines.
The state-controlled minerals firm made a net profit of 311 million riyals ($82.93 million) compared with 27 million riyals in the prior-year period, it said in a bourse statement.
Net income for the second-quarter was 128 million riyals.
Five analysts polled by Reuters expected the company to post an average third-quarter profit of 241 million riyals.
Maaden said the increase in third-quarter net income was "attributed to the beginning of commercial production of ammonia and DAP" as well as "higher realised price and quantity sold of DAP, ammonia and gold".
DAP is di-ammonium phosphate, which is used to make industrial fertiliser.
The partly state-owned company is in a phase of rapid production growth, with plans to build a new $1.5 billion aluminium refinery, add a new line to an existing aluminium smelter, and invest $5.6 billion in a phosphate project.
In June, Maaden said it had received bank commitments for a 7 billion riyal Islamic loan. ($1 = 3.7502 Saudi riyals) (Reporting by Angus McDowall Editing by Rachna Uppal)