Lombok NTB

East Lombok Regency, West Nusa Tenggara Province

The main digging materials potential in East Lombok Regency is pumice, sirtu, stone, limestone and clay, while limited in number is silica stone. Stone type, pumice and sirtu are found in numbers; because this region is ± 85% closed by volcanic rock resulted from eruption sediment of Mt. Rinjani.
Various digging materials type has been mined. Pumice, stone and sirtu are mostly mined, although its local people mine type. Digging of clay for brick making has been conducted in some places. Pumice mining location is mostly found in Ijobalit Countryside, Labuhan Haji Sub District, while sirtu mining is spreading in some place, for example in Sub District of Labuhan Haji, Suralaga, Masbagik, Pringgasela and Wanasaba. Stone mining which is conducted by society on a small scale in Pringgasela Sub District; while big enough stone mining is conducted by private enterprise in Pringgabaya Sub District. Clay digging is mostly conducted in Montong Gading Sub District by local society for brick making. Mineworker in investigation area generally conducts its activity by simple method without correct technique, therefore, negative impact to environment is occurred in some places, even endanger to mineworker safety themselves, like forming of straight bank with height between 4 m and 13 m, even hanged bank exists, pond occurred in mine area and mudding into creek around mine area.
Various mine material type is spreading widely in some places. Pumice for example are found in Ijobalit area, Labuhan Haji Sub District, and North Jenggik, Montong Gading Sub District; sirtu is found in Sub District of Aikmel, Suralaga, Masbagik and Labuhan Haji; stone is spreading over all Mt. Rinjani foot and body occupying Sub District of Sembalun, Sambelia, Pringgabaya, Wanasaba, Suela, Aikmel, Pringgasela, Sikur, Terara and Jerowaru; clay is found in area Sub District of Montongbetok and Sikur; silica stone and limestone id found in Jerowaru Sub District. However, according to consideration of environmental geology aspect and also land used at and around digging materials location, not all digging materials can be mined.
Mining feasibility of digging materials deposit has to be determined its 2 criteria beforehand that are environmental geology and non geology aspect. Study of environmental geology aspect occupies condition of topography, rock type and formation (including thickness of over burden), hydrogeology condition, physical and technical characteristic of soil (technique geology), geology disaster, and protected area of geology. Criteria of non geology aspect occupies social, economics, cultural and land used.