Derivatives of tricyclo-[5.2.1.0.sup.2,6 ]-dec-3-ene corresponding to the following general formula ##STR1## in which R.sup.1 is hydrogen; a linear or branched C.sub.1 -C.sub.8 alkyl radical; an acyl radical R.sup.2 -CO, where R.sup.2 is hydrogen or a linear or branched C.sub.1 -C.sub.18 alkyl or alkenyl radical; or a hydroxyalkyl radical ##STR2## in which R.sup.3 and R.sup.4 independently of one another may be hydrogen or a hydroxy group and m and n are integers of 0 to 5 and the sum (m+n) is an integer of 1 to 5, with the proviso that at least one of the radicals R.sup.3 and R.sup.4 is a hydroxy group; are used as frothers in the flotation of coal and ores.