Skripsi
PERENCANAAN NORMALISASI SALURAN IRIGASI SEKUNDER UNTUK LAHAN SAWAH DESA RUKUN MAKMUR KECAMATAN PULAU RIMAU
PT. Pacific Granitama Tanjung Balai Karimun is one of the companies that mines granite. Granite is a common type of intrusive rock and is commonly found. This rock was formed as a result of slow crystallization from liquid magma deep within the earth's crust. Minerals, which form granite, are generally quartz, feldspars, and other minerals. Granites are mostly large, hard and strong, and are therefore widely used as rocks for construction. Backbreak is excess damage or cracks behind the end of the explosive hole. The presence of this backbreak is not wanted or avoided. PT. Pacific Granitama uses nonel in hole delay and nonel surface delay produced by PT. Dahana. In the in hole delay the delay is 500 ms. For surface delay, there are four types that are most commonly used. Delay time value in nonel surface delay is 17 ms, 25 ms, 42 ms, and 67 ms. The blasting geometry used at PT. Pacific Granitama is V-Cut and Corner Cut. In the blasting geometry the number of rows used is 3 rows and 4 rows. The blasting geometry has spacing of 3,6 – 3,7 m, burden of 3,0 – 3,2 m, diameter of 4,5 inches, stemming 3 m, subdrilling 1 m, drilling angle of 10o, and a depth of 17,3 m. The size of the backbreak is calculated by comparing the area of the blown up to the area of the field that was supposed to explode. The field that should have been blown up was found by mapping the final blast hole point. After blasting, the points outside the exploded plane are mapped. Comparison of backbreaks that occur is expressed in percent. Calculation of the percentage of backbreak area on a 3 rows blast pattern is 14,71%. Calculation of the percentage of backbreak area on a 4 rows blasting pattern is 19,65%. The use of overall delay both column delay (front) and row delay affect the amount of backbreak that occurs. The use of smaller row delay than column delay results in a larger backbreak.
Inventory Code | Barcode | Call Number | Location | Status |
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2307002413 | T112875 | T1128752023 | Central Library (Referens) | Available but not for loan - Not for Loan |
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