* H2 profit down 15 pct to $6.12 bln, misses forecasts
* Final dividend 59 cents v 60 cents consensus
* To invest $2.6 bln to progress Jansen potash project
* BHP says may sell down stakes in Jansen
By Sonali Paul
MELBOURNE, Aug 20 (Reuters) - Top global miner BHP Billiton missed forecasts with a 15 percent fall in half-year profit, and said it will slow down a long-awaited move into potash to curb spending over the next four years.
BHP and Glencore Xstrata wrapped up the results season for the world's big five miners, with BHP holding up slightly better than its peers as it stepped up output of iron ore, copper, coal and oil and slashed costs in the face of sliding commodity prices.
Major miners have come under pressure to rein in spending, sell off underperfoming assets and tackle debt after years of rampant spending on new mines and acquisitions as commodity prices soared.
BHP put more than $40 billion worth of new projects on ice a year ago to combat costs that had grown out of control over the previous decade as miners raced to feed booming Chinese demand.
Handing down his first results, new Chief Executive Andrew Mackenzie outlined a more aggressive cut in capital and exploration spending than recently flagged, with spending to fall 26 percent to $16.2 billion in the 2014 financial year.
BHP plans to invest $2.6 billion to finish digging shafts and installing infrastructure for the Jansen potash project in Canada over the next four years, but did not give any timetable for actually starting production.
While delaying the start-up from an original target of 2015, it also said it may sell down stakes in the project to one or more partners over time.
"I think it's a vote of confidence in the project. We strongly believe that over decades to come this has the potential to deliver significant returns to our shareholders," Mackenzie said on a conference call.
The company cut $2.7 billion in operating costs in the 2013 financial year.
Attributable profit excluding one-offs fell to $6.12 billion for the six months to June from $7.18 billion a year ago. That was well below analysts' forecasts of $7.16 billion, according to Thomson Reuters I/B/E/S.
BHP increased its final dividend by 2 cents to 59 cents, just short of analysts' forecasts at 60 cents.
BHP has long planned to break into the potash industry, targeting a lucrative new business that has been controlled by two cartels, as developing countries look to grow more food over the next few decades.
It has already invested $1.2 billion in Jansen and the timing of its entry has been closely watched by the world's major producers, led by Potash Corp of Saskatchewan, which BHP tried to take over in 2010.
Its $39 billion bid was blocked by Canada on fears that potash prices and royalties would drop as BHP planned to split from the North American cartel. Now Russia's Uralkali has given potash producers a taste of what could happen as it recently quit the Belarusian Potash Co cartel.
BHP's shares have jumped 20 percent off a one-year low hit in June, bolstered by iron ore price rises that have defied fears of cooling Chinese growth.