Experiments conducted with limestone dusts and dolomitic marble dusts have indicated that when rock dust is wetted and subsequently dried, it becomes a solid, non-dispersible cake. However, in order to be effectively inert a coal dust explosion, rock dust must be able to disperse as individual particles to air. To counteract this, rock dust manufacturers created treated rock dusts that will resist caking after moisture exposure. National Institute for Occupational Safety and Health (NIOSH) researchers conducted a series of laboratory-scale experiments on four base rock dusts and their treated counterparts to assess the effectiveness of various anti-caking additives after being exposed to moisture and then dried. The dusts were exposed to moisture using humidity cabinets having a high relative humidity (99% RH) and by also exposing the rock dust bed to water through bottom wicking. The dusts were then evaluated for dispersibility after drying using the NIOSH-designed dust dispersion chamber. The anti-caking additives were different concentrations of stearic acid, oleic acid, and xylene-based surfactants. All results were compared to a reference rock dust used to conduct large-scale experiments in the Lake Lynn Experimental Mine (LLEM), Fairchance, PA. When the untreated dusts were dried after exposure to moisture for 1 day, no dispersion was measured. However, rock dusts treated with anti-caking agents were readily dispersible even after exposure to moisture for 6 months. This report details the analysis and characterization of anti-caking additives using the NIOSH-designed dispersion chamber and the 20-L explosion test chamber.

用石灰石粉尘和白云石大理石粉尘进行的实验表明，将岩石粉尘润湿并随后干燥后，它将变成固体的，不可分散的饼。但是，为了有效地抑制煤尘爆炸，岩屑必须能够作为单个颗粒散布到空气中。为了解决这个问题，粉尘制造商制造了经过处理的粉尘，这些粉尘在受潮后会结块。美国国家职业安全与健康研究所（NIOSH）的研究人员对四种基岩粉尘及其经过处理的对应粉尘进行了一系列实验室规模的实验，以评估各种防结块添加剂在暴露于水分然后干燥后的有效性。使用具有较高相对湿度（相对湿度为99％RH）的湿度柜，以及通过底部芯吸使岩石粉尘层暴露于水中，使粉尘暴露在湿气中。然后使用NIOSH设计的粉尘分散室对干燥后的粉尘进行分散性评估。抗结块添加剂是不同浓度的硬脂酸，油酸和二甲苯基表面活性剂。将所有结果与在宾夕法尼亚州Fairchance的Lake Lynn实验矿（LLEM）中用于进行大规模实验的参考岩粉进行了比较。当未处理的粉尘暴露于湿气1天后干燥时，没有测量到分散体。但是，经防结块剂处理过的岩粉即使在潮湿环境中放置6个月也很容易分散。