The present study developed a suitable foam dust-remove device for down-the-hole (DTH) drilling in open-pit mines and researched its foaming properties to solve the resulting serious dust pollution. We researched the foam dust removal mechanism and two-phase foaming principle to improve the disadvantages of traditional dust removal technology such as poor effects, big air consumption and water intake difficulties. We obtained the main factors that influence the foaming performance and optimum working point of the foam generator based on performance tests on the foam flow, foaming multiple, and half-life period of the foam generator. Based on the experimental results, the gas flow rate, liquid flow rate (gas liquid ratio), foaming net, and foaming agent concentration were deemed the four main factors that affected the foaming performance of the foam generator. The following working conditions were operated: (1) foam net 1; (2) A 1.5% concentration of the formulation 2; (3) gas pressure of 0.7 MPa; (4) liquid flow rate of 18 L/min; (5) gas flow rate of 30 m(3)/h. Based on these conditions, the foam generator achieved its best performance with a foam flow rate of 515 L/min, foaming multiple of 22, and half-life of 65 min. The average dust removal rate throughout the field test was as high as 90% using foam dedusting in stope. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.