The blast, at a makeshift gold-panning site at Gomgombiro in the southwest of the country, happened when a stock of dynamite blew up, said local officials and hospital staff, France 24 reported.
Images showed a large blast site of felled trees and destroyed tin houses. Bodies lay on the ground, covered in mats.
A hospital source said: “At least five casualties have succumbed to their wounds, bringing the toll to 55,” adding that the toll could rise as some of the injured were in critical condition.
Women and children were among the 60 or so injured in the blast, many of them in a critical condition, the source said.
It was not clear exactly what kind of gold mining went on at the site. Burkina Faso is home to some major gold mines run by international companies, but also to hundreds of smaller, informal sites that operate without oversight or regulation.
Children frequently work in these so-called artisanal mines; accidents are common.
Burkina Faso, one of the world’s least developed countries, is under attack from Islamist groups linked to al Qaeda and Islamic State who seek control of mining sites as a means to fund their violent attacks.
Monday’s blast was hundreds of miles from where these groups usually operate and there was no sign that Islamist militants were involved.