Thong tin khoa hoc cong ngh# m o
,/i»ldT s o G l A l P I I A P LAM YEU Stf BO DA VACH KHI KHAI THAC LO CH0 COT DAI THEO PHl/OfNG
t r o n g d i e u k i e n v a c h k h o d i e u k h i e n
Roof control is considered very important, direcUy inffuencing the safety level and mining efficiency in longwall mining operations. Bad roof control will create high ground pressure on coal faces and supports, causing a lot of failures which need to be treated. The paper refers to some solutions for preliminahly weakening the roof rock in longwall advancing on strike method with hard roof control
TS. L E OO'C NGUYEN TS. D A O N G O C H O A N G
KS. DU-C/NG BCTC HAI Vi$n Khoa hgc Cdng nghd Md - Vinacomin
Bien tap: TS. Dao Hong Quing
I . D g t v d n d l
Dieu khiln dd vdch la mOt cdng doan rdt quan trpng, quylt dinh tryc tilp den hieu qua vd an todn trong khai thde Id chp'. Trinh t y giai phdp dieu khiln dd vdch eho 16 chp cot ddi theo phuong la thyc hign edng tac phd hda ban ddu trudc khi dua 16 ehp' vao hoat dpng. Tiep dd, trong qud trinh khai thac thyc hign pha hoa thudng ky, da vdch t y sgp do phia sau 16 chp theo budc gly thudng ky. Tuy nhien, trong dilu kign da vdch khd dieu khien (vdch khd sap d l , vdch ngng), cdng tde pha hda ban d i u khdng giai quyet dupe vIn d l dp lye md Idn, k l ca vigc dp dyng pha hoa thudng ky cudng buc. Khi do, d l dam bao d\eu khiln dup'c dp lye md cua 16 ehp, d n phai ed nhung giai phap khae. Thue t l , mot so md da hop tac vdi Vign Khoa hpe Cong nghg Md - N^nacomin nghien cuu, dp dyng giai phap dieu khien giu dd vdch tren cdc try than bao ve (via 10, Hong Thai, via 11 (46), Trdng Bach), tr§n eac dai try bao vg nhdn tao (via 4, Khe Chuoi), hoac tren ede dai than luu (via 15, Nga Hai). Cdc giai phdp ndy da eo ban da giai quyet dupe dp lye mo Idn tai khu vyc 16 cho hogt dpng, song nhupc dilm chung la cong tde to chdc san xuat phuc tap, ndng suit lao ddng thap.
Bai viit neu mpt s i giai phdp Idm y l u so bg dd vdch khi khai thdc Id chg cpt ddi theo phuong trong dieu kign vdch khd dieu khiln.
2. Mpt sd gidi phdp lam y l u so* bp da vach t r u ^ c khi pha hod
Tren t h i gidi, de dilu khiln dd vdch trong trudng hp'p vach khd sgp d l , vdch ngng, thudng ap dyng cdc giai phap lam yeu so bp da vdch, bang cdch su dyng ede phuong tign (thulc n l , thuy lye) tdc dpng tryc tilp vao khoi da d l dua
dd vdch ve dgng d l sap d l hoac sap do trung binh. Mpt so giai phap thudng dup'c dp dung tai eae md than ham Id tren t h i gidi nhu: no min t i i n trude trong Id khoan ddi, no min k i t hpp xu ly thuy lye, n l min bua nude trong lo khoan ddi, su dyng xung thuy lye, tgo phan ldp da vach eo ban bdng thuy dpng lye.
- Ldm ySu da vach bang giai phap 'no min tien trudc trong 16 khoan dai": Ban chit eua giai phap ndy Id Idm y l u so bp vdch eo ban phfa tru'dc guong 16 chp' bang cdch no min trong ede Id khoan ddi. Dudi tac dyng eua vigc no min, da cung cua vdch co ban bi pha huy tgo ra eac he thong khe nut nhan tao lam y l u khli da. Qua dd, lam giam manh eudng dp vd tai trpng cua ldp vach eo ban tac dpng len vi ehIng 16 ehp.
Phuong phdp nay dup'c thyc hien tai eac md him 16 eua be than Karaganda (Lien bang Nga).
Vdi cac guong 16 ehp co chieu dai den 120m dp dyng so do bo tri Id khoan tu mot phia (hinh la). Cdc guong 16 chp ddi hon 120m dp dyng so do b l tri Id khoan t u hai phfa (hinh lb). Giai phdp ndy c6 t h i dp dyng trong ca dilu kien phd hoa ban dau dd vdch khd sap d l vd vdch nang.
Trong gidi phap ndy, khoang cdch giua cdc Id khoan (a) phy thude vdo dac ^ I m da vdch Theo kinh nghigm tai eae md than ham 16 thupc b l than Karaganda, khoang each nay thudng tu 14 •*• 27m. Khoang each day cua cac 16 khoan t u 16 dpc via thdng gid vd t u 16 dpc via van tai trong so d l b l tri Id khoan t u hai phia (d) tu 10 - 20m.
Gde khoan (p) phu thupc vao hudng he thong khe nut t u nhien cua khoi da vd thudng tu 50 •*•
80" hoae 90°. Gdc nghieng cua Id khoan (9) tu 6 -5-17°. Khoang cdeh vudng gdc tu via than d i n vj tri ngp min thIp nhlt trong Id khoan (hHr) tu 3 -s-
KHCNM S 6 4/2016 * CNKT HAM LO
Thdng tin khoa hoc cona nah§ m o
a Sa dd bd tri Id khoan tCF mdt phia b. So dd bd tri Id khoan tu- hai phia Hinh 1. Sa dd cdng nghd Idm yiu dd vdch bdng
khoan nd min tiin truuc 4m. Khoang each tu via than d i n vi tri ngp min cao nhat (hex) t u 10 -^ 20m. Dudng kinh Id khoan phy thupc vao he s i kien c l cua dd (0- Vdt dd CO f < 8, dudng kinh 16 khoan t u 75 -^ 93mm. Dd CO f >8 dudng kinh 16 khoan den 112mm. Chilu dai nap min khi dudng kinh 60mm khong Idn hon 100m
Kinh nghiem dp dung tgi cdc md hdm Id d be than Karaganda cho thIy, khi khoang cdeh giua cdc hdng lo khoan nhu nhau doi vdi ca 3 Iogi da vdch khd sap do, gia tri cua bude sap do eua da vdch tryc tilp vd dd vdch co ban cd su thay d l i khdc nhau, trong dd, budc sgp d l cua vdch tryc tiep giam tu 30 -=• 40%, cdn budc sap do cua vdch eo ban vdi da nhdm 1 giam 10 -^ 15%, da nhom 2 giam 25 - 30% vd da nhom 3 giam 35 - 40% hoae Idn hon (theo bang phdn Iogi da vach eua vien VNIMI - Lien bang Nga).
Giai phap no min tien trude c6n c d t h i thyc hign theo m0t trong hai phuong phap sau' (1) No min gida man ehln: myc dich cua phuong phap ndy Id dam bao su dyng toj da ndng lupng n l d l ndng cao t i i da kha ndng Idm y l u dd vach, loi dung ede khe nut ty nhien hoae khe nut nhan tao. Cae l5 khoan dupe b l tri vao cdc khe nut cho phep su dyng higu qua toi da dng suit cua sdng phan xa no min; (2) lam y l u e6 dinh hudng, ban chit cua phuong phap ndy la md rpng mat pha huy t u nhien bang each no min trong mpt Id khoan dai con 16 ben canh khong nap no min - "16 ty do". So do nhu vgy ddn den vigc giam sdng ehln dpng len dd y l u cua vdch tryc tilp, cho phep giam tut noc.
- Lam yeu di vach bang "no min ket hgp x u iy thuy li/c": Ban chat phuong phdp nay Id hinh thdnh trudc sy ndt ne trong khli da eua da vach kho sap do va nguydn khli bang n l mm trpng eac lo khoan ddi dudng kinh 36 -^ 38mm, khli lupng thulc n l 35 -^ 50kg sau do tdm I m da vach bang each bom nudc vao Id khoan vdi ap lye 0,5-1,0 MPa. Sau tac dpng cua vy n l vd lam am dd, qua trinh sgp do cua dd vdch eo ban khi khau guong diln ra binh thudng.
Cdc thdng s i co ban eua phuong phdp lam y l u da vach bang n l min k i t hpp xu ly thuy lye bao gIm. khoang each t u phln nap thulc thap nhlt trong lo khoan den via than (hHi); khoang each t u phan ngp thulc cao nhat trong lo khoan d i n via than (hsr); chieu ddi lo khoan (ICKB);
dudng kinh 16 khoan (dcKs); khoang each giua cdc 16 khoan (a); khoi lupng thulc n l (Q); goc khoan theo hudng tiin guong (p); g6c khoan so vdi via than (9). Khi 16 chp' co ehieu ddi den 120m, su dyng so do bo tri lo khoan tu mpt phia (hinh 2a), khi chilu dai Id ehp Idn hon 120m su dyng so do bo tri 16 khoan td hai phia (hinh ve 2b). Kinh nghiem dp dyng trong eae md tgi Lien bang Nga thudng chpn gid trj hKi khong nhd hon 5m, gid trj her dup'c xde djnh t u cong thdc:
hHT = m/1-Kr
Trong dd m - chieu day khai thac cua via than, m; Kr - hg s i nd rdi cua dd vdch eo ban (dli vdi da bpt k i t khd sgp do Kr = 1,2, vdi da eat k i t Kr= 1,5).
Chieu ddi lo khoan khi ap dyng so do bo tri mpt hudng va eac thong s i cua chung dupe tinh toan sao eho khoang cdch tu day 16 khoan d i n dudng 16 chuan bj khdng nhd hon 4m (hinh 2a), vdi so do bo tri 16 khoan t u hai phfa, khoang cdch giua eac day Id khoan td 16 thong gio va 16 vgn tai tu 3 -^ 5m (hinh 2b). Dudng kinh 16 khoan thudng chpn bang 42mm.
Khoang cdeh giua cae lo khoan a = 2 Racjj, trong do, Rodp - Id bdn kinh vCing xu ly thuy lue sau khi bom ep nudc, thudng chpn tu 7 -s- 8m.
Chilu dai phln ngp thulc n l trong l l khoan khong vupt qud 30m- Gdc khoan P phy thupc vao 16 chp vd dupc tinh todn sao eho gdc giua 16 khoan vd thd cua dat dd tgp thanh 30°. Sau khi khoan n l min, tiin hanh bom ep nude vdi thdi gian khdng nho hon 6 gid.
- No min bua nimc trong lo khoan dai: Ban chat cua phuong phap nay la Idm thay doi ede KHCNM s o 4/2016 * CNKT HAM L 6
Thdng tin khoa hoc cong nghe md
a-sodd bd tri l6 khoan ti> mdt phia;
b- sa dd bd tri l5 khoan td- hai phia Hinh 2. Sa dd cdng ngh$ lam ySu dd vdch
bdng nd min kSt hop xu- /y thuy ILK tinh chit CO ly cua dd md bdng tac dpng thuy lye kit hpp vdi vigc cho no min mpt lugng nho tgi eac vi tri mat tilp xuc gida cdc khli dd hay tgi eac ldp dd y l u vd no trong moi tnj'dng ngdm nudc vdi dia khoi dupe Idm yeu bdng thuy lye.
C6 t h i noi, phuong phdp ndy id sy k i t hgp cac ede giai phdp ho min tien trudc vd n l thuy luc.
Phuong phap no vi thuy lye dupe dp dyng vdi cdc Iogi da vach vd hg thing khai thac bit ky, cho phep dp dyng trong cdc md than h i m 16 c6 nguy co n l khi, no byi cung nhu eac md co nguy eo phyt khi vd than bit ngd No min bua nude eung co the dugc su dyng de xu ly cdc khu vuc via than vdi da vdch ngng.
Cac thong so eo ban cua phuong phap nay bao gIm: chieu cao tu day 16 khoan d i n via than (h3); chilu ddi lo khoan (ICKB); dudng kinh 16 khoan (dcKB); khoang each giua cdc 16 khoan (a); khli lupng thuoc nd (Q); gdc khoan theo hudng tien guong (P); goc khoan so vdi via than (6). Khi id chg cd chieu dai d i n 120m, su dyng so do bo tri 16 khoan tu mpt phia, khi ehilu ddi 16 chg Idn hon 120m, su dyng so do bo tri 16 khoan t u hai phia (tuong t y hinh 1 a vd hinh 1 b).
Khoang cdeh gii>a eac day Id khoan td 16 vdn tai vd 16 thdng gid vdi so d l bo tri Id khoan t u hai phia lay bang 2 lan ban kfnh lam udt hieu qua iZRsdp). Ban kfnh lam udt hieu qua duoc xde djnh theo eong thue:
0 , 0 4 XnXl^XT Trong do: Q>K - tdng the tieh chit long dua 3016 khoan, m^; i« - chieu ddi phln 16 khoan d l
1.3. bua min; 2. thudc nS; 4 lo khoan ddi; 5. via than;
Hinh 3. Sa dd cdng nghe Idm ySu dd vdch bdng nd min bua nieOc trong Id khoan ddi hd, m; mo - dp ring, %.
Chilu cao t u day 16 khoan den via dupe xde djnh theo cong thuc:
hs = hjio + 0,6 Ra* + (4 -^ 5)m _ Trong d6: hno - chilu ddy eua ldp da vdch de sap d l , m; m - chilu ddy khai thac cua via than, m.
Chilu ddi Id khoan khi dp dyng so d l b l tri 16 khoan tu mpt phia dugc tinh toan sao cho khoang cdch t u day 16 khoan den dudng 16 kh6ng Idn hon Racf) nhung khong nho hon 5m.
Khi dp dyng so d l b l tri lo khoan tu hai phia, chilu ddi lo khoan dugc xde djnh de dam bao khoang each giua cdc ddy lo khoan la 2R343 . Dudng kinh 16 khoan t u 75 - 112mm. Khoang cdeh eae 16 khoan eho dd vach vdi he s i kien CO f > 8 tu 20 - 30mm, vdi dd vach co f > 8 tu 16 -^ 25m. Ting khoi lugng thulc n l dong thdi trong mot 16 khoan khdng Idn hon 27kg. Thulc no trong moi 16 khoan dugc dat vdo vi tri lien k i t yeu eua vach eo ban, de nang nupng no lam taeh ldp da vach khd sap do. Tuy thupc vao cae vj tri lien kit y l u ngudi ta tien hanh xac dinh so lupng vd vi tri dat thuoc no. Vigc n l min dupc thyc hign d ngodi vung dp lye tya.
Goc khoan p phu thupc vdo hudng cua hg thing nut ne vd thudng t u 50 -^ 80°. Gdc quay 16 khoan theo hudng guong 16 chg dugc xac d\n\\ dam bao vung tdc dpng thuy lye nam ngodi vung dp luc tua, bdi vi khi do cdc nut ne hinh thdnh tai phln tren cua 16 khoan xay ra sdm hon phan gan mieng 16 khoan. Tac dpng thuy lye cua dd vdch kho sap d l Id mpt trong nhung nhan to co ban eua phuong phap n l vi thuy lye.
- Lam yeu da vach su" di^ng xung thuy lijo: Id phuong phdp tgo ra ede khe nut e6 dinh hudng
KHCNM SO 4/2016 * CNKT HAM LO
Thong tin khoa hoc cong nghe mo
1. Cdc lo khoan; 2. Ranh khai didm Hinh 4. Sa dd cdng nghd Idm ySu dd vdch b^ng
xung thuy li/c cd dinh hudng trong dd vdch co ban nhd vigc bom nude d c h i dp xung thuy lye. So do cdng nghg eua phuong phdp ndy t h i hign tren hinh 4. Ban chit cua so do cong nghg nay la tu 16 chg hoac cdc dudng 16 dpe via tiin hanh khoan cdc 16 khoan dai len vdch d l tao rgdi sau do bjt kin mieng 16 khoan vd bom ep nudc d c h i dp "xung" thuy lye (nen ep khong lien tye). Phuong phdp ndy khde vdi phuong phdp n l vi thuy lye d cho khdng su dyng thulc no. thay vao do, hodn todn su dyng ndng lupng thuy lye cung cdc 16 khoan tgo rach ban dau de d t dd vdch thanh cac khoi nho hon, tgo dilu kign thugn Igi eho cdng tdc phd hda ban ddu trong cdc khu vyc via than cd vdch kho sgp d l .
Qk gidm tai trpng cua bude pha hoa ban dau da vdch eo ban, ngudi ta thudng dp dyng 2 so d l phdn bo 16 khoan nhu sau: (1) Cdc i l khoan 1 dupe khoan vdi mpt goc hpp vdi thd eua dia tang vd theo hudng tiin guong t u 16 khdi diem, cdc raeh 2 dupe tgo dpc theo tryc eua cdc 16 khoan d l lam y l u so bp dd vdch trudc khi khai thdc (hinh 4a); (2) Cdc 16 khoan dugc khoan vdi mpt gde hpp vdi via theo hudng vdo khoang kh6ng gian da khai thde, cac rgeh 3 dupe tgo vudng gde vdi tmc cua eac 16 khoan (hinh 4b).
De gidm tai trpng khi ha vdch co ban, so d l hinh 4e dupc su dung, cdc Id khoan dugc khoan liln k l vdi khu vyc 16 chg.
- Giai phap tao phan lop da vach cabin bing thuy dong li/c: Giai phdp nay duge su dyng d l lam y l u lien k i t giua cdc ldp da cua vach co ban khi phd hda ban d i u tai cdc via than ed da vdch khd sap do hoge vdch ndng. V\^c phdn ldp da vach co ban cdn dugc su dyng trong phd
KHCNM SO 4/2016* CNKT HAM LO
1. Cdc l6 khoan; 2. Vi ch6ng Id che; 3. Cdc nCrt n§
trong da vdch; 4. RSnh khdi diim.
Hinh 5. So dd cong ngh$ tao phdn ldp dd vdch ca bdn bdng thuy ddng It/c
hda thudng ky tgi cdc khu vyc via than cd vdch ngng do tdp vdch eo ban ddy bj taeh lam ede phdn ldp mdng hon, suy yeu va sgp d l , b l sung cho ldp vdch tryc tilp cd chilu ddy khdng du Idn (nhd hon 6 -s- 7 l l n ehilu ddy khai thac cua via) Chen d l y khoang khdng gian da khai thac.
So do edng nghe phan ldp dd vdch co ban bIng thuy dpng lye dugc t h i hien hinh 5.
Phan ldp da vach bdng thuy dpng lye dupc thyc hien bang cdc^ khoan eac Id khoan ddi vdo dd vdch de hinh thdnh ranh khdi dilm tgi dp cao duge xac djnh tiieo chilu ddy vach co ban vd bom chat Idng vdo d ehe dp xung thuy lye. Nhd tde dpng eua xung thuy lye, ranh d t duge md rpng ttieo hudng da <^nh trude. Theo kinh nghigm triln khai dp dyng tgi cac md him 16 cua Lien bang Nga, dudng kinh Id khoan td 45 -5- 93mm, dudng kfnh cua rdnh d t khdi diem lly bang 1,8 •*• 2 lan dudng kinh l l khoan. Phdn ldp da vach bang thuy dpng lye dugc thyc hign t u cae dudng 16 chuln bj va bo tri ngodi vung dp lye tya cua 16 chg, d khoang cdch t u 70 + 100m d i n 16 chg. Cdc mdy bom d n su dyng Iogi eo luu lugng t u 100 I/phut hoge dCing 2 + 3 mdy bom CO t i n g luu lugng dam bao yeu d u ndy
3. K i t lu^n
Trong thdi gian tdi, khi cac md him 16 vDng Quang Ninh ngay cang khai thdc xudng sdu, vIn d l dilu khiln dp lye md ngdy cdng phdc tgp.
Vi$c dp dyng cac gidi phdp Idm ylu so bd dd vach Id r l t c i n thilt. Do do, d n tilp tyc nghiSn CUTJ, phdt triln dk tiin tdi Idm chu cdng nghg vd ding bd thilt bj Idm y l u so b0 dd vdch phyc vy eong tac khai thdc than Id chg an todn, hi#u qud./.