Farida Afriani Astuti Doctoral Program of Environmental Science, School of Postgraduate Studies, Diponegoro University, Semarang-Indonesia
Faculty of Mineral Technology, Universitas Pembangunan Nasional Veteran Yogyakarta , Yogyakarta-Indonesia Indonesia
Syafrudin Syafrudin Faculty of Engineering, Diponegoro University
Indah Susilowati Faculty of Economics and Business, Diponegoro University Indonesia