Abstract: A borehole mining process for recovery of petroleum from unconsolidated heavy oil formations. The process consists of drilling a borehole in the unconsolidated heavy oil reservoir, which is formed from sand particles aggregated by heavy oil, and positioning a casing and a first and second tubing string within the borehole. At least one nozzle is positioned on the lower end of the second tubing string and is oriented for fluid emission generally radially outwardly from the second tubing string. Fluid is then flowed downwardly through the second tubing string and outwardly through the nozzle, thereby eroding a cavity in the reservoir and forming a slurry consisting of the fluid, the heavy oil, and the particles from the reservoir. The slurry is flowed upwardly through the annulus between the first and second tubing strings to the upper end of the borehole for recovery of the heavy oil.