Underground mines use a system of passes to transfer by gravity the ore from the upper levels of the mine to the crushing and hoisting site. In the majority of cases, passes control ore flow in these openings. Often subject to blockage, these passes represent safety risks to workers when they have to clear them. The researchers evaluated the effectiveness of the different types of ore passes most common in the Québec mining industry and the dimensioning rules proposed in the literature. This report describes their evaluation, which takes into account the impact of the geometry of the systems in question on blockage formation. An ore pass design guide accompanies the report. As a result, mining engineers will be better equipped to develop and implement safer systems adapted to the particular needs of each mine.