P PT. Cibaliung Sumber (PT. CSD) is engaged in gold mining located in Cibaliung District, Labuhan Regency, Banten Province and adjacent to the Ujung Kulon National Park. Cibaliung has 2 mining locations, namely Cibitung Block and Cikoneng Block, which can be accessed through 1 portal, namely the Cikoneng portal. At the time of the study the conditions of the Cibitung Block were being conducted while there were no mining activities (the study was focused on the Cikoneng block). many workers complained about the actual conditions in the field, including the high temperature (dry convex temperature (Td): 27 ° C - 33 ° C, wet convex temperature (Tw): 26 ° C - 33 ° C, and relative humidity (Rh ): 89% - 100%) on location. The other problem that occurs in the air in the Cikoneng Block is the lack of clean air discharge to each XC through the Air Duct (Vent Duct). From these results it can be concluded that the temperature on the working front in the Cikoneng Block is very bad because it is not in accordance with the KepMen 555 standard which has a standard of 18 ° C-24 ° C and for humidity. For the moisture data from the results of research conducted in Cikoneng Block ranges from 89% -100%, where this value is not in accordance with KepMen 555 standard which has a standard <85%, this indicates that the humidity level in the Cikoneng Block is very high. from the heat coming out of the heavy equipment and rocks in the Cikoneng Block. The ventilation system in the Cikoneng Block is currently unable to meet the needs of its workers due to the lack of air supply flowing towards the work fronts. The need for repairing the ventilation network with the addition of 37 kw fan for each working front.