2.1.2. AII database

The AII database includes each reportable occupational safety and health (OSH) incident that a mine experienced during the course of a given year. Each case within the database represents an individual OSH incident and, therefore, each case exists at the individual worker level. However, each reportable OSH incident is linked to a specific mine through their unique mine identification code, as assigned by MSHA. Using the MSHA-required form 7000-1 (MSHA’s Mine Incident, Injury, and Illness Report), mines must record and report each of the following events:

This list includes incidents that resulted in worker injury as well as events that did not result in an injury but could have (i.e., a near miss). Within the AII database, there are numerous variables associated with each reported incident. For example, the degree of injury variable codes each OSH incident as a fatal injury, an injury that resulted in a permanent disability, an injury that resulted in days lost or restricted duty (herein referred to as days lost injuries), or a reportable injury (those without lost or restricted days), or a near miss.

Each of the datasets demarcated by year were summarized individually. For each mine, the total number of fatalities, near misses, and each type of injury was summed. Given that the AII database includes information only if a mine reported an OSH event during a given year, an active and operating mine with zero reportable OSH incidents during a given year would not have any associated cases in the AII database. To correct this, all active status mines were isolated using the AE databases for each year during the time period studied. The number of fatalities, permanently disabling injuries, days lost injuries, near misses, and total number of lost and restricted days each mine experienced were added to the set of active mining establishments. Zeros were then imputed for each of the OSH incident variables for the years in which a mine was active but had no case identified within the AII database.