Identifying Delay Time of Detonator for a Millisecond Blasting

Based on wavelet transform, the blasting vibration signals are analyzed here. For millisecond blasting, the blasting effect is mostly affected by the actual delay time. Local characteristics of the analyzed signals could be highlighted by the wavelet transform. The simultaneous initiation of large explosive quantity could be avoided by the use of multistage detonators, while the vibration resistance effect could be better. For the same level of detonator segment, the larger the arranged time interval, the less the possibility of initiation at the same time, which is not conducive to the vibration resistance. Therefore, it is suggested to use high-level detonators with detonating cord or high-precision digital electronic detonators to minimize the initiation error. Furthermore, by identifying the delay time using wavelet transform, the interval delay time of different detonator segments could be obtained. Moreover, the nominal delay time, actual delay time, and interval delay time are further compared and analyzed. It is suggested that the millisecond delay series of detonators should be selected in the whole section blasting, and the segment should be jumped as much as possible, so as to increase the secondary breakage time. Detonators with longer interval delay time should be avoided to the full.

PENINGKATAN KUALITAS FRAGMENTASI DAN DIGGING TIME DENGAN MENGGUNAKAN DETONATOR ELEKTRONIK DI PIT CMD PT KALTIM PRIMA COAL

ABSTRAK Salah satu faktor penting yang mempengaruhi kualitas hasil peledakan adalah tingkat keakurasian waktu tunda dari sistem inisiasi peledakan yang digunakan. Saat ini, peledakan di Pit PAMA CMD PT Kaltim Prima Coal (PT KPC) menggunakan detonator non electric (nonel) yang memiliki tingkat keakurasian waktu tunda sebesar ±97-98% dari waktu tunda rencana. Hasil analisis fragmentasi menggunakan software WipFrag™ dan pengukuran digging time pada peledakan nonel menunjukkan % passing 300 mm (P30) sebesar 80,64% dengan digging time 11,10 detik di Pit Pelikan dan P30 sebesar 82,66% dengan digging time 10,41 detik di Pit Kanguru. Ukuran fragmentasi pada peledakan nonel di Pit PAMA CMD aktualnya telah memenuhi standar ukuran fragmentasi yang diterapkan di PT KPC yaitu P30 ≥ 80%, namun masih terdapat potensi untuk meningkatkan hasil ini dengan menggunakan detonator elektronik DigiShot™ Plus (DS+). Penggunaan DS+ yang memiliki tingkat keakurasian waktu tunda mencapai ±99.8% dari waktu tunda rencana, selain dapat meningkatkan kualitas ukuran fragmentasi juga dapat memperbaiki digging time dan mengurangi penggunaan Lead in Line (LiL) dengan aplikasi remote firing. Hasil peledakan DS+ di Pit Pelikan menunjukkan P30 sebesar 86,24% atau 5,6% lebih tinggi dibanding peledakan nonel dengan digging time 10,22 detik atau 7,9% lebih cepat dibanding peledakan nonel. Sementara data yang didapat di Pit Kanguru menunjukkan P30 sebesar 87,55% atau 4,9% lebih tinggi dengan digging time 9,66 detik atau 7,2% lebih cepat dibanding peledakan nonel. Data ini didapatkan dari penggunaan DS+ sebanyak 8.541 unit di 89 lokasi peledakan di Pit Pelikan dan Pit Kanguru PAMA CMD PT KPC. Selaras dengan peningkatan pada kualitas fragmentasi dan digging time, peledakan DS+ di Pit PAMA CMD juga berkontribusi terhadap perbaikan produktivitas alat gali yang meningkat ±2,5% dan penghematan penggunaan LiL sepanjang 49,8 km. Dapat disimpulkan, penggunaan detonator elektronik pada peledakan sangat berpotensi untuk meningkatkan kualitas hasil peledakan dan penghematan biaya peledakan jika diaplikasikan dengan optimal. Kata kunci: elektronik, fragmentasi, digging time ABSTRACT One important factor that influences the quality of blasting results is the accuracy of the delay of the blasting initiation system used. At present, the blast activity at PAMA CMD Pit PT Kaltim Prima Coal uses a non-electric (nonel) detonator which has a delay time accuracy of ± 97-98% of the planned delay. The results of fragmentation analysis using WipFrag™ software and measurement of digging time on nonel blasting showed % passing 300 mm (P30) was 80.64% with digging time of 11.10 seconds in the Pelikan Pit and P30 of 82.66% with digging time of 10.41 seconds in the Kanguru Pit.The size of the fragmentation in nonel blast at PAMA CMD Pit actually has met the standard fragmentation size applied at PT KPC which is P30 ≥ 80%, but there is still potential to increase this result by using the DigiShot ™ Plus (DS +) electronic detonator. The use of DS + which has an accuracy of delay time reaching ± 99.8% of the plan delay time, not only to increase the quality of the fragmentation size, but also improve digging time and reduce the use of Lead in Line (LiL) with remote firing applications. The results of DS + blasting in Pelikan Pit showed P30 was 86.24% or 5.6% higher than nonel blasting with digging time 10.22 seconds or 7.9% faster than nonel blasting. The data obtained in the Kanguru Pit showed P30 was 87.55% or 4.9% higher with a digging time of 9.66 seconds or 7.2% faster than nonel blasting. This data was obtained from the use of DS + as many as 8,541 units in 89 blasting locations in the Pelikan Pit and the Kanguru PAMA CMD Pit PT KPC. In line with the improvement in the quality of fragmentation and digging time, DS + blasting in the PAMA CMD Pit also contributed to improved digging equipment productivity which increased by ± 2.5% and savings in the use of LiL along 49.8 km. It can be concluded, the use of electronic detonators in blasting has the potential to improve the quality of blasting results and blast cost savings if applied optimally. Keywords: electronics, fragmentation, digging time