We don't have synonyms for slickens yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are slacken, slicker and dickens.
(n) :
(originally US dialectal) Fine, harmful, and (when wet) slimy pulverized rock, a waste product (pollution) produced by hydraulic mining and quartz milling, which can silt up rivers and accumulate on soil downstream of such activities.
(n) :
(originally US dialectal) Fine, harmful, and (when wet) slimy pulverized rock, a waste product (pollution) produced by hydraulic mining and quartz milling, which can silt up rivers and accumulate on soil downstream of such activities.