KAJIAN TEKNIS PENGURANGAN TINGKAT GETARAN TANAH YANG DIHASILKAN PADA OPERASI PELEDAKAN OVERBURDEN TAMBANG BATUBARA PIT 2 BANKO BARAT PT. BUKIT ASAM Tbk, TANJUNG ENIM
Daftar Isi:
- One of the mining activities in PT. Bukit Asam Tbk is overburdens removal. The methods to remove the overburdens are drilling and blasting. Overburdens at Pit 2 Banko Barat generally consist of sandstones, although this type of stone are relatively soft, blasting operation is still needed for equipment maintenance purpose. One of the issues that occur from blasting is ground vibration. Ground vibration that produced by blasting operation can cause some problems for structures around blasting area and its slope stability. One of blasting site that affected from this issue is Banko Barat which is located within 1100-1300 m from residential areas, although this site is quite far enough but some of blasting operation generate ground vibration that quite high. And this issue this what makes some citizens worry. The methods and steps in this research is consist of determine the problems, literature’s references, field’s observation, collecting data, data analysis, data processing, then the conclusions. The data analysis was done by using the theory of geometric regression equation, the relationship between the scaled distance and peak particle velocity to estimate the level of ground vibrations to be generated. Ground vibration level measurements carried out on 24 December 2017-29 April 2017 and obtained 17 data of ground vibration level. There are 3 data that over standard limit ground vibration levels which are 3,429 mm / s, 4.191 mm / s, and 5.461 mm / s which allowed values of ground vibration is 3 mm / s. Ground vibration level at 4.191 mm/s and 5.461 mm/s has distance over 555 m and 640 m where this distance has not entered residential areas. Therefore there is possibility at 1100 – 1300 m distance the ground vibration will generate smaller level. After analyzing the geometric regression equation, obtained form the equation Y = 2706 X -1.552 which can be converted into peak particle velocity equation is PPV = 2706 SD-1,522. After the estimation of ground vibration levels on the previous blasting activities, it was found that there is no blasting activities that produce ground vibrations that pass through the boundary where the vibration level for the biggest stuffing per delay / hole is 100 kg only generate ground vibrations at 1.837 mm / s. Safe distance limit for the value of the biggest stuffing per delay / hole of 100 kg required a minimum distance of 830 m in order that ground vibrations to be generated under the prescribed limits. And for the value of the smallest stuffing per delay / hole of 55 kg required minimum distance of 610 m.