(New throughout, adds government promise to continue rescue efforts)
By Jimmy Sanchez
BONANZA, Nicaragua Aug 29 (Reuters) - Rescue workers have freed 22 miners who were trapped in a gold mine after a landslide in northern Nicaragua, and the government on Saturday vowed to continue search efforts for several workers that remained stuck underground.
Some 29 miners were trapped on Thursday after heavy rains provoked a landslide at the mine in the Bonanza project, about 260 miles (420 km) northeast of Managua, which was closed about four years ago after being deemed unsafe.
Rescue teams will continue search efforts, after freeing two miners on Thursday and another 20 on Friday, according to Rosario Murillo Ortega, government spokesman and wife of Nicaraguan President Daniel Ortega.
"We are monitoring the situation, following up on all efforts to find the five or seven companions," Murillo said on Saturday.
Artisanal mining is legal in Nicaragua, the poorest country in Latin America, where it is used as a way for more people to profit from the industry.
Bonanza project mine had been severely affected by seasonal rains in the past, with another landslide two months ago killing two miners, according to Mineros S.A., the Colombian parent company of Nicaraguan miner Hemco, which operates the mine.
Informal miners continued to work at the mine against the company's orders, according to Julio Quintero, head of Hemco.
Quintero said Hemco had continued to buy minerals from them until last week, when it decided it could not be sure where the product came from.
The Bonanza project, which began in 1995, produces around 37,300 troy ounces of gold a year, according to Hemco's website. (Additional reporting by Leslie Nicolas Lacayo; writing by Alexandra Alper; editing by Tom Pfeiffer and David Gregorio)