Thong tin khoa hoc cong nghe m o
CONG NGHE KHAI THAC LOP BAUXIT TREN SU'dN DOC
ThS. D 6 NGOC Tl/dC KS. DOAN VAN THANH
KS. vu OINH TRL/ONG
Vien Khoa hgc Cdng nghe Mo - Vinacomin Because of the valuable mineral, at present, bauxite has been exploited and processed for meeting the demands of export and domestic consumption. According to investigated results, most of bauxite ore bodies at Tan Rai area are distributed on the high sides. Therefore, applying proper mining technologies to recover natural resources, saving production cost and minimizing environmental pollution is an essential task
diem mo bauxit 1. Dac
Tan Rai
a. Dac diem dia hinh Md bauxit Tan Rai thudc phan phia ddng cua cao nguyen Bao Ldc - Di Linh, khu md dap'c phan bd tren dja hinh cd dp cao 800 - 900m, be mat dja hinh cd dang ddi gd dinh trdn sadn thoai bj phan each bdi nhang thung lung dai va hep. Dp nghieng cua khu md cd hadng ddc d i n t a Ddng Bac xudng Tay Nam.
Dieu kien dja hinh khu md cd anh hLPong quyet djnh den chit lap'ng va tra lu'p'ng cac than quang bauxit. Cf nhang noi cd dja hinh cao taong ang vdi phan dinh cac ddi, mat dja hinh taong ddi bang p h i n g quang bauxit cd chat lu'p'ng trung binh va khdng dn djnh nhLPng chieu day than quang Idn. Nhang noi cd dja hinh thoai (doc du'di 5°) chat laong quang bauxit t a trung binh den tdt.
O nhang dja hinh thap du'di sat chan ddi chat lu'p'ng quang bien doi manh. Dadi thung lung g i n cac ddng va
khdi nadc mat, vd phong hoa bao hoa thi quang bauxit khdng phat trien.
Trong pham vi khu md p h i n Idn quang bauxit nam d p h i n dinh ddi cd dja hinh cao (chiem 87%), mdt p h i n nam d sadn ddi nhang chu yeu v i n nam tren mac nu'dc n g i m .
b. Dac diem tinh chat co>
ly
Dja tang khu md Tan Rai, ta tren xudng bao gdm cac Idp: Ldp da't phu cd chieu day 0,5m; Ldp laterit - bauxit cd chieu day ta 3+3,5m; Ldp bauxit - laterit cd chieu day ta 7+-10m; Ldp litoma cd chieu day ta 1,5^2,0m. Cac Idp dat tren dadc khai thac trac tiep khdng can khoan nd min, chi
Dja tang
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r r r ^ r r '~ ^ r r r r
Ode diem Ldp d^t phu lan q u d n g Bauxit Ldp laterit - Bauxit
L6p Bauxit - laterit
L6p litoma
L6p bazan phong hoa L6p bazan tuai
Hinh 1- Cdt dja tang md Tan Rai
cd phan quang tang chiem 10^11% khdi laong khai thac, cd dp cOng f = 8-9 (theo phan loai cua Prdtddiacondp) tadng daong vdi gidi han ben nen 5„
= 80^90 MPa can phai lam tdi so bd trade khi khai thac.
C i u true cdt dja t i n g md Tan Rai daoc the hien tren hinh 1.
2. Phan bo tru luong bauxit Quang bauxit d md Tan Rai tao thanh cac via phan bo d phan dinh cac plate va it khi phat trien tdi tan sadn plato.
Tren toan dien tich cdng tac 42km^, vd phong hoa laterit chaa bauxit phu g i n 32 km^
chiem khoang 75 %. Quang tinh bauxit dat chi tieu cdng nghiep (lay theo chi tieu quang tinh: AI2O3/4O %, modun silic/7, day /1m, dd thu hoach tinh quang + 1 mm/20) dapc khoanh ndi vao than quang tinh tra lu'p'ng cd dien tich 20,3 km^ chiem khoang 48 %.
Quang bauxit khdng dat chi tieu cdng nghipp thadng nam d s a d n hoac ria plato hoac p h i n day cac dam l i y . Quang bauxit cdng nghiep cd be day Idn thLPdng tap trgng d phan dinh cac plato, cd noi dat be day 11m (G03-35). Be day cua bauxit d dinh plato Idn hon va c h i t lap'ng cua chung
cung tdt hon so vdi bauxit n i m d sadn. Gdc ddc dja hinh rat anh hadng den s a phan bd cua
via bauxit.
ThLPong sadn ddc cua dja hinh
> 25° thi bauxit laterit bj rCpa trdi, trong khi dd, neu
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gdc ddc su-dn ta 11°-15° thi bauxit cdn rat nhieu d su-dn, nhieu tru'dng hp'p quang phan bd tdi^tan^day thung lung. Sa bien ddi be day cua via bauxit tren toan md khdng Idn. Qua ban dd ddng gia tn be day quang va ban dd ddng gia tri ham laong, dp thu hdi quang tinh cho thiy tai cac plato khu vac phfa bic, tay bac md Tan Rai, dja hinh tu'ong ddi bang phang thi chit lap'ng quang va be day via bauxit dn djnh va Idn hon cac than quang khu Ddng Nam.
* D$c diem Idp bauxit tren sudn doc
Dac diem Idp bauxit tren sadn ddc cd cac dac diem sau: Dja hinh ddc nghieng ve cac phfa vdi gdc ddc 11°^15°
tao thanh dang Idng chao.
Chieu day that trung binh cCia Idp phCi: 0,45m; chieu day (that) Idp quang thay ddi ta Im+IOm trung binh cua Idp quang 5m. Chieu day nan\
ngang cOa Idp quang thay ddi ta 16m+24m, Idp phCi thay ddi ta 1,5m+4,5m. Be mat dja hinh dadc bao phCi bdi cay ca phe va cay thdng cua dan.
3. Yeu cau khai thac ldp bauxit
Quang bauxit la ngudn tai nguyen Idn cua nadc ta, la co sd de hinh thanh nganh cdng nghipp luypn nhdm, la ngudn lac quan trpng trong qua trinh cdng nghipp hoa, hipn dai hoa dit nu'dc. Hipn nay, do chu-a san xuat dap'c cho nen chung ta phai nhap toan bp nhdm va trong taong lai cung vdi sa phat trien kinh te, nhu c i u ve nhdm cdn Idn hon naa. Mat khac, thi tru'dng nhap khau nhdm cac nadc xung quanh
cung rat Idn. Dieu dd ddi hdi chung ta phai khan tru'ong phat trien cdng nghipp khai thac bauxit va luypn nhdm cang sdm cang tdt de dap ang nhu ciu trong nadc va hadng tdi xuat khau nhdm khi cd dieu kien.
Vdi ngudn tai nguyen quang bauxit da xac djnh, neu daqjc dau ta khai thac va che bien quang bauxit se ddng mpt vai trd ra't quan trpng cho nen kinh te va qua trinh cdng nghiep hoa cCia da't nadc. Khi nganh cdng nghiep alumin - nhdm dapc hinh thanh se giam daoc mdt laong ngoai te Idn dung de nhap khau nhLf hien nay.
Vi vay, cin phii nghien cau laa chpn cac cdng nghe khai thac nham dam bao cac mgc tieu sau:
- Khai thac tdi da ngudn tai nguyen bauxit.
- Khai thac vdi cdng nghe ma tdn that va lam ngheo quang la nhd nhat.
- Khai thac vdi cdng nghp va thiet bj don gian, quen thupc vdi trinh dp cdng nhan khu vac.
- Khai thac dam bao than thipn vdi mdi tradng^
4. Cong nghe khai thac
De tan dung dien tfch cac day thung lung khdng quang lam chd chCfa tam dat phu chd phgc vu hoan thd, bao dam cung dp van tai dat phCi nhd nhat, thuan Idi cho cdng tac thoat nadc va^ ket hop giOra cdng tac thai da't mat va cdng tac *' hoan thd, trinh ta khai thac "
phan sadn cac plato se dapc tien hanh ta phan
thap len phan cao. Tren dpc chieu dai tuyen cdng tac phan ra thanh cac khdi khai thac (block) kfch thadc phu hop vdi thiet bj sCr dgng va an toan lao ddng.
Tuy thudc vao chieu day nam ngang cua than quang bauxit tren sadn doc. Cdng nghe khai thac bauxit tren sadn ddc dap'c phan ra lam cac tradng hp'p sau:
a) Cong nghe khai thac xuc quang true tiep bang may xuc va chat tai len oto.
may gat gat dat phu.
Nhufng khu vac cd chieu day nam ngang cua quang
>15m -17m du de dtd quay dao chieu va nhan tai. Khi dd sCr dung cdng nghe xuc tru'c tiep, may xuc dCrng d mCrc trung gian cOa tang cdng tac vdi gaong phdi hdp, cha't tai vao dtd dChig d mac dadi. So do cdng nghe dap'c md ta tren hinh 2. Sd d6 nay cd au diem la nang suat ddng bd thiet bj Idn.
IUTCXTA^
Hinh 2. Sa do cdng nghe khai thac bang may xuc
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b) Cong nghe khai thac sij' dung may gat.
- NhOmg khu vac cd chieu day nam ngang cCia quang
<15m -17m khdng du chieu rdng cho dtd quay dao chieu.
Khi dd, khdng the xuc trac tiep va dp doc cho may gat hop ly, quang dap'c gat ta phin cao cua block khai thac xudng
lac gau ngu'p'c xuc len dtd van chuyen ve xadng tuyen, hoac cung cd the xuc trac tilp quang len dtd. So do cdng nghe the hien tren hinh 3.
c) Cong nghe khai thac SLF dung may phay cat
Vdi dieu kien ap dgng may phay cat ddi vdi cac loai da't da cd gidi han ben nen 5^ < 80+-90 Chan tang de may xuc thuy MPa. Nha vay, vdi dieu kien khu md Tan Rai cac Idp
S 0 D 6 H T K T P H A N SUdN PLATO
Hinh 3- Sado cdng nghe khai thac bang may gat
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Hinh 4-Sado cdng nghe khai thac bang may phay cat (sa do khau quay vdng)
dat va quang phfa tren daoc khai thac tare tiep khdng can khoan nd min, chi cd phan quang tang chiem 10% ^ 11%
khdi ladng khai thac, cd dp cCing f = 8 +- 9 (theo phan loai cCia
Prdtddiacondp) tadng daong vdi gidi han ben nen 6^ = 80+90 MPa can phai lam tdi sd bd tnidc khi khai thac. Vay viec ap dung thCr nghiem cdng nghe khai thac bang may phay cat tren sadn ddi ra't hieu qua.
can ca vao ket qua danh gia dac diem dieu kien dia chat cac khu vac ap dgng cdng nghe bdc dat bang may phay cat; dieu kien khai thac cua md;
de xua't laa chpn may phay cat mang ma hieu 2200 SM hoac 2500 SM cua hang Wirtgen.
Khu vac sadn ddi cd chieu day quang nam ngang ta 5m+-24m, tuy thudc vao chieu dai
khai tradng cd the sCr dung cac so do khau sau:
+ Khau lien tuc
Khau lien tuc quay vdng tren sadn thung lung: sau khi dung may gat gat gom Idp dat phu xadng chan va lam^ dadng cho dtd va may ta dinh ddi xudng day thung lung daa may vao kha'u vdng trdn tren toan thung lung. 6td nhan tai phfa trade, khi day se van tai ra dadng ve bai chaa.
Be rdng mat tang cdng tac tdi thieu dapc tfnh toan phu thudc be rdng cua dtd theo cdng thCfc:
B^in = 2Bo + B,+ 2Li +L2 + L,, m
Trong dd: B^, BQ la be rdng cCia may khau va dtd,m
Li: khoang each giaa may va dtd khi tranh nhau, m.
L2, L3 khoang each an toan ta mep tang va chan tang tdi mep ngoai cCia dtd.
Be rdng B^in Cmg vdi may kha'u 2200SM, 2500SM.
+ Khau tai xuong chan tang Khi be rdng nam ngang cua quang > B^ va < 8 -10m (taong Cmg vdi may khau 2200Sm va 2500SM thi may kha'u se kha'u va tai xudng dadi. Tai chan tang quang se dadc may xuc xuc len dtd chd ve bai chCfa.
+ Khau khdng lien tuc
+ Khi chieu day nam ngang cua quang >8m-10m va < 15-17m (taong Ong vdi may kha'u 2200Sm va 2500SM) sCr dung cac sd do cdng nghe khau 2 chieu.
Kha'u hai chieu (tai khu vgc quay dau se khdng cat tai) (hinh 6).
Cac thdng sd cdng nghe ddi vdi may 2200SM:
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c-c
Hinh 5- Sado cdng nghe khai thac bang may phay cat ( khau tai xuong chan tang)
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Hinh 6- Sa do cdng nghe khau 2 chieu Hinh 7 -Sa dd cdng nghe khau mdt hudng Chieu rdng bloc kha'u: 10
m<B< 17m
Chieu dai kha'u I >150 m.
+ Kha'u 1 chieu, hadng ngaoc lai khdng tai khi chieu dai khu vac khau < 150m;
chieu rdng < 2Rq (hinh 5). 6 t d lui vao nhan tai khi day se van tai quang ve bai chaa.
Cac thdng sd cdng nghe:
Chieu dai bloc: <150 m Chieu rdng: Bo + L2 + L3<
B^i, < 2B, + L1+L2 + L3.
d. Cong nghe khai thac hdn hop may xuc + may gat + may phay cat
Do dac diem phan bd cua cac than quang bauxit tren sadn ddc la khdng ddng deu, gdc ddc thay ddi 11°-15° tao thanh dang Idng chao cd day.
Chieu day that trung binh cua Idp phu: 0,45m; chieu day (that) Idp quang thay ddi ta 1+-10m trung binh cua Idp quang 5m. Chieu day nam ngang cua Idp quang thay ddi ta 10m+-24m, Idp phu thay ddi ta 1,5m-^4,5m. Vay, LAJ tien nhufng khu vac nao cd chieu day nam ngang cua than quang Idn hon chieu rdng quay dao chieu cua dtd thi ap dgng cdng nge xuc trac tiep bang may xuc (phan a), nhong khu vac cd chieu day nam ngang than quang nhd hon chieu rdng quay dao chieu cua thiet bj van tai thi ap dgng cdng nghe gat xudng chan tuyen sau dd dung may xuc de xuc len dtd va van tai ve bai chaa (phin b). Nhufng khu vac cd gdc ddc sadn ddi nhd va chieu rdng dam bao cho may
phay cat lam viec thi ap dung cdng nghe khai thac Idp bauxit tren sadn ddc bang may phay cat (phin c).
Ket luan
Bauxit la khoang san cd gia trj. Viec tim kiem cac cdng nghe - thiet bi mdi hien dai, cd ddng, nang suat cao, ft lam anh hadng mdi tnJdng va gia thanh ha la hadng di dung dan cho nganh khai thac Id thien Viet Nam.
Vdi dac diem cac than quang bauxit Tan Rai nam tren sadn ddi chiem ty le tadng ddi Idn, viec ap dung cac cdng nghe khai thac hdp ly" nham tan thu tdi da tai nguyen va tiet kiem chi phf san xuat, dam bao khdng gay d nhidm den mdi tradng la het sCrc can thiet./.
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