* Conflict has lasted nearly half a century
* All past peace talks with FARC rebels failed
* Guerrillas slam oil and mining companies
By Balazs Koranyi and Helen Murphy
HURDAL, Norway/BOGOTA, Oct 18 (Reuters) - Colombian government and leftist rebel negotiators agreed to meet in Cuba in mid-November to start what are likely to be thorny peace talks aimed at patching together an end to half a century of conflict, both sides said on Thursday.
Talks, which opened in Norway this week, are the latest in a long history of attempts to resolve the war which has left tens of thousands dead and millions more displaced since the founding of the Revolutionary Armed Forces of Colombia, or FARC, in 1964.
Colombian President Juan Manuel Santos is betting that a decade of U.S.-backed blows against the FARC has battered the group to the point it will seriously seek to end the fighting after so many previous efforts ended in shambles.
But in the first sign of discord, rebel leader Ivan Marquez slammed foreign oil and mining interests in Colombia, saying their presence was destructive and should be discussed. Humberto de la Calle, the government's lead negotiator, ruled that out.
"The peace process will be successful if it is serious, realistic and efficient," de la Calle said in Hurdal, Norway.
"We are not discussing the model of economic development. We are not discussing foreign investment. For that to be discussed on the Colombian agenda, the FARC have to lay down their arms, enter politics and win elections," he said.
In a carefully stage-managed event, Norwegian organizers were able to avoid what became a symbol of the failure of the last attempt at peace in 1999: a vacant chair. Back then, a red-faced President Andres Pastrana sat next to the empty seat of FARC founder Manuel Marulanda, who failed to turn up.
This time, the two sides appeared jointly on Thursday at a plush hotel - the first time they have met publicly in a decade. The negotiators entered the conference room together, then sat at a table with representatives of Cuba and Norway between them. They did not talk or shake hands.
The government delegation sat stone-faced as Marquez spoke for half an hour following short opening remarks by de la Calle. The sides then held separate press conferences.
The negotiations move to Cuba on Nov. 15 and will begin a five-point agenda with discussions about rural development. The last talks were held in a tent deep in the Colombian jungle.
"The spirit of the agreement is clear and you don't need to find a theologian to interpret it. We'll work within the spirit," said FARC negotiator Jesus Santrich, wearing dark glasses and carrying a walking cane.
"We are embracing this process and I would like to say to (de la Calle): 'take it easy, we're just starting.'"
Peace with the FARC will by no means end violence in Colombia as drug trafficking and criminal gangs - many born out of the demobilization of right-wing paramilitary groups - will continue to operate across the nation.
Many Colombians believe it will be impossible to absorb the thousands of FARC fighters, many of whom are illiterate, into an already difficult job market, and there are fears some rebels could turn to cocaine trafficking.
Although ten years of strikes against the FARC - which has funded its war by kidnapping, extortion and drugs - have cut its ranks by more than half and put its leadership on the run, defeating the rebels with military means alone has proved difficult, leaving a negotiated deal as the best alternative.
Santos, who faces re-election in 2014, says the government wants to reach a deal in a matter of months, not years, while the FARC says it will sit at the table as long as necessary, which was reiterated by Marquez at the opening of the new talks.
"Marquez's expressed opposition to achieving a peace agreement 'against the clock' is a clear signal that the group will attempt to prolong and extend the process as long as possible," said James Lockhart Smith of the Maplecroft risk consultancy.
"There is very unlikely to be a definitive agreement ... before the campaign for the 2014 presidential elections begins again in Colombia."
In a tone reminiscent of previous FARC statements, Marquez criticized international mining companies and rich Colombians for buying up land at the expense of the rural poor, accusing by name the sons of former President Alvaro Uribe.
Uribe, credited for the U.S.-backed offensive that weakened the FARC, is among the most vocal critics of the talks, saying Santos has sold out in a bid for a place in the history books at the expense of security. Uribe denied Marquez's accusations in a Twitter message on Thursday.
Latin America's fourth-largest oil producer has seen a boom in oil and mining investment over the past decade, as improved security attracted an influx of dollars. Santos' government has called the sector a "locomotive" for growth.
The bearded and bespectacled Marquez, wearing a dark suit and white shirt, lashed out specifically at Cerrejon, Drummond, BHP Billiton and AngloGold Ashanti Ltd
"The energy and mining locomotive is like a demon of social-environmental destruction. If the people do not stop it, in less than a decade it will convert Colombia into an unviable country," Marquez said.
Foreign direct investment this year is expected to reach about $17 billion, a record, and well above the $2 billion it attracted in 2002 when Uribe took office. Back then, the FARC was at its strongest and able to launch attacks in Bogota.
In the capital, dozens of family members of FARC kidnap victims gathered in a main square, wearing black T-shirts with colour photos of their missing parents, sons and daughters.
"We want to know the truth. We want them to give us back our family members," Amparo Bustos, whose 71-year-old father is being held by the rebels, said in an appeal on local television.
"Alive or dead, we want to know the truth."