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PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
Diketahui: Ht
= Tinggi Runtuh (m)
PRMR
= Beban Batuan (ton/m3)
qt
= Beban persatuan panjang (ton/m2)
σsf
= Kelas Kuat Kayu(ton/m2) (lihat table)
σb
= Tegangan Pelengkungan (ton/m2)
a
= Spasi penyangga
lb
= Lebar beban batuan (m2)
b
= Lebar penampang kayu persegi = 0.2 m
h
= Tinggi penampang kayu persegi = 0.2 m λ
= Angka kerampingan
w
= Faktor penekukan kayu (lihat table)
Qy
= Beban samping (ton/m) Lapisan Mudstone Claystone Mudstone Coal Mudstone
Lebar Span (m) 5 5 5 5 5
Densitas (ton/m3) 2,2 2,1 2,2 1,6 2,2
RMR 49 40 39 44 39
a (m) 1 1 1 1 1
Lebar Kayu = 20 cm = 0,2 m Tinggi Kayu = 20 cm = 0,2 m Ditanya : 1. Faktor keamanan rancangan Cap ? 2. Faktor keamanan rancangan Side Post ? 3. Faktor keamanan rancangan Siring dan Wedge ? Penyelesaian : 1. Rancangan Cap a. Lapisan Mudstone Ht
=
100−RMR 100
x lebar span
PERHITUNGAN PENYANGGA
PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
ht
=
100−49 x5m 100
= 2,55 m PRMR
= ht x Densitas
PRMR
= 2,55 m x 2,2 ton/m3 = 5,61 ton/m3
qt
= PRMR x a
qt
= 5,61 ton/m2 x 1 m = 5,61 ton/m3
FK mudstone
σb
=
=
σsf σb
0,125 x qt x lb bh 2 6
=
0,125 x 5,61ton/ m x 1 m 0,177 x 0,2 m x (0,2 m)2
2
= 524,888 ton/m2 FK lapisan Mudstone
=
σsf σb
=
1100 ton /m 2 524,888 ton/m
2
= 2, 096 (aman) b. Lapisan Claystone Ht
=
100−RMR 100
ht
=
100−40 x5m 100
x lebar span
= 3m PRMR
= ht x Densitas
PERHITUNGAN PENYANGGA
PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
= 3 m x 2,1 ton/m3
PRMR
= 6,3 ton/m3 Qt
= PRMR x a
qt
= 6,3 ton/m2 x 1 m = 6,3 ton/m3
FK Claystone
σb
=
=
σsf σb
0,125 x qt x lb bh 2 6
=
0,125 x 6,3 ton /m x 1m 0,177 x 0,2 m x (0,2 m) 2
2
= 556,144 ton/m2 FK lapisan Claystone
=
σsf σb
=
1100 ton /m 2 556,144 ton/m
2
= 1,9 (aman) c. Lapisan Mudstone ht
=
100−RMR 100
ht
=
100−39 x5m 100
x lebar span
= 3,05 m PRMR
= ht x Densitas
PRMR
= 3,05 m x 2,2 ton/m3 = 6,71 ton/m3
qt
= PRMR x a
PERHITUNGAN PENYANGGA
PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
= 6,71 ton/m2 x 1 m
qt
= 6,71 ton/m3
FK Mudstone
σb
=
=
σsf σb
0,125 x qt x lb bh 2 6
0,125 x 6,71ton/m x 1m 0,177 x 0,2 m x (0,2 m) 2
=
2
= 627,806 ton/m2 FK lapisan Mudstone
=
σsf σb
=
1100 ton /m 2 627,806 ton /m
2
= 1,7 (aman)
d. Lapisan Coal ht
=
100−RMR 100
ht
=
100−44 x5m 100
x lebar span
= 2,8 m PRMR
= ht x Densitas
PRMR
= 2,8 m x 1,6 ton/m3 = 4,48 ton/m3
FK Coal
σb
=
=
σsf σb
0,125 x qt x lb bh 2 6
=
0,125 x 4,48 ton/m x 1 m 0,177 x 0,2 m x (0,2m)2
2
PERHITUNGAN PENYANGGA
PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
= 395,480 ton/m2 FK lapisan Coal
=
σsf σb
=
1100 ton /m 2 395,480 ton/m 2
= 2,7 (aman) e. Lapisan Mudstone Ht
=
100−RMR 100
ht
=
100−39 x5m 100
x lebar span
= 3,05 m PRMR
= ht x Densitas
PRMR
= 3,05 m x 2,2 ton/m3 = 6,71 ton/m3
qt
= PRMR x a
qt
= 6,71 ton/m2 x 1 m = 6,71 ton/m3
FK Mudstone
σb
=
=
0,125 x qt x lb 2 bh 6
σsf σb
0,125 x 6,3 ton/m x 1m 0,177 x 0,2 m x (0,2 m)2
=
2
= 627,806 ton/m2 FK Mudstone
=
σsf σb
PERHITUNGAN PENYANGGA
PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
=
1100 ton/m2 627,806 ton/m 2
= 1,7 (aman) 2. a.
Rancangan Side Post K
μ = 1−0,30 =
b.
c.
σy
0,30 =0,408 1−0,30
= K x PRMR
σ y lapisan mudstone = 0,408 x 1,22 ton/m2
= 0,457 ton/m2
σ y lapisan claystone = 0,408 x 1,26 ton/m2
= 0,514 ton/m2
σy
lapisan mudstone = 0,408 x 1.342 ton/m2
= 0,547 ton/m2
σy
lapisan coal
= 0,408 x 0,896 ton/m2
=0,365 ton/m2
σy
lapisan mudstone =0,408 x 1,342 ton/m2
=0,547 ton/m2
qy
= σy x spasi
qy lapisan mudstone
= 0,457 ton/m2 x 1m
= 0457 ton/m2
qy lapisan claystone
= 0,514 ton/m2x 1m
= 0,514 ton/m3
qy lapisan claystone
= 0,547 ton/m2 x 1m
=0,547 ton/m2
qy lapisan coal
= 0,365 ton/m2 x 1m
=0,365 ton/m2
qy lapisan mudstone
= 0,547 ton/m2 x 1m
= 0,547 ton/m2
PERHITUNGAN PENYANGGA
PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
d.
λ
=4
post ( Panjang Tinggi Balok )
=4
( 0,25 mm )
= 4,25 = 100 e.
w
= f (λ) λ
= 2,036
FK Side Post σb ≤ σsf (aman) 2
σb=−0,5 ( ω )
σy .(ly) qt .lb ± 0,637 bh bh2
FK lapisan Mudstone σb=−0,5 ( 2,036 )
0,457ton /m2 ( 5 m ) 2 1,112 ton/m 3.1m ± 0,638 0,2 m. 0,2 m 0,2 m ( 0,2 m ) 2
= - 28,3004 ton/m2 ± 911,14 ton/m2 (+) = 882,839 ton/m2 (-) = - 939,4404 ton/m2 σsf 1100 ton/ m2 = FK= σb 882,839ton /m2 = 1,2 (aman) FK lapisan Claystone
PERHITUNGAN PENYANGGA
PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
σb=−0,5 ( 2,306 )
0,514 ton/m 2. ( 5 m ) 2 1,26 ton/m 3.1m ± 0,638 0,2 m. 0,2m 0,2 m . ( 0,2 m ) 2
= - 32,067 ton/m2 ± 1024,7875 ton/m2 (+) = 992,713 ton/m (-) =1056,84 ton/m2 FK =
σsf 1100 ton/m2 = σb 992,713ton /m2 = 1,1 (aman)
FK lapisan Mudstone σb=−0,5 ( 2,036 )
0,547 ton/m2. ( 5 m ) 2 1,342ton /m3.1 m ± 0,638 0,2m .0.2 m 0,2 m ( 0,2 m ) 2
= -34,1539 ± 1090,58 (+) = 1056,4 (-) = -1124,73 σsf 1100 ton/m 2 = FK = σb 1056,4 = 1,0 (aman) FK lapisan Coal σb=−0,5 ( 2.036 )
0,365 ton/m 2.(5 m) 0,869 ton/m 3.1 ± 0,638 0,2 m.0,2 m 0,2 m ( 0,2m ) 2
= -22,8032 ton/m2 ± 727,718 (+) = 704,9148 ton/m2 (-) = - 750,5212 ton/m2 σsf 1100 ton/m2 = FK = σb 704,9148 ton. m 2 = 1,5 (aman)
PERHITUNGAN PENYANGGA
PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
3.
Rancangan Siring / Wedges hk
hk a.
1 /2
= 0,865 . a
σy σsf
( )
1 /2
= 0,865 . a
σy σsf
( )
(Tebal Siring untuk bagian samping)
(Tebal Siring untuk bagian atas)
Lapisan Mudstone hk (untuk samping)
= 0,865 . 1 m
(
0,457 ton/m 2 2 1100 ton/m
1 /2
)
= 0,017 m = 1,7 cm = 2 cm hk (untuk atas )
= 0,865 . 1m
(
2 1 /2
)
1,122ton/m 2 1100 ton/m
= 0,027 m = 2,7 m = 3 cm
b.
Lapisan Claystone hk (untuk samping)
= 0,865 . 1m
(
2 1 /2
)
0,514 ton/m 1100 ton/m 2
= 0,018 m = 1,8 cm = 2 cm hk (untuk atas )
= 0,865 . 1m
(
1,26 ton/m2 1100 ton/m2
1 /2
)
= 0,029 m = 2,9 m = 3 cm c.
Lapisan Mudstone hk (untuk samping)
= 0,865 . 1 m
(
2 1 /2
0,547 ton/m 2 1100 ton/m
)
= 0,019 m = 1,9 cm = 2 cm
PERHITUNGAN PENYANGGA
PT.REBELAVA UNDERGROUND MINING COAL DESIGN | 2016
hk (untuk atas )
= 0,865 . 1m
(
1,342ton/m2 1100 ton/m2
1 /2
)
= 0,030 m = 3 cm d.
Lapisan Coal hk (untuk samping)
= 0,865 . 1 m
(
2 1/ 2
)
0,365 ton/m 2 1100 ton/m
= 0,015 m = 1,5 cm = 2 cm hk (untuk atas )
= 0,865 . 1m
(
0,896 ton/m 2 1100 ton/m 2
1 /2
)
= 0,024 m = 2,4 cm = 3 cm Jumlah kebutuhan penyangga/ kayu untuk terowongan: Kayu yang digunakan dlam 1 set penyangga
= 8 buah kayu/m
Jarak dari lubang bukaan ke tempat penambangan
= 2578,4075 m
Jumlah kayu yang dibutuhkan
= 8bh/m x 2578.4075 m = 20.627 bh =1587 kubik
Jumlah kebutuhan penyangga/ kayu untuk room : Kayu yang digunakan dlam 1 set penyangga
= 8 buah kayu
Jarak room yang akan disanggah
= 23.442,75 m
Jumlah kayu yang dibutuhkan
= 8bh/m x 23.442,75 m = 187.542 bh = 14.427 kubik
PERHITUNGAN PENYANGGA