Pulverizers in a power plant are used to grind coal in the form of find power for combustion. To secure reliable operation, redundant pulverizers are installed in the power plant. If the current health condition and remaining useful life of a gearbox system in each pulverizer are estimated correctly, the pulverizers can be operated and maintained in a cost-effective manner. To this end, a Data Challenge Committee in the PHMAP 2017 conference is organized to run an open competition. This paper presents the original problem and observed facts as well as the list of winners of the Data Challenge Competition. We anticipate that this paper can be used as a reference in the development of a prognostic method that can predict the health conditions of the pulverizers accurately.