KHOA HOC VA CONB NGHE M O
_ ^ ^
"^GHIEN c d u ANH HlliiNG CUA LAM NGHEO QUANG
T d i HIEU QUA CUA D U A N KHni THnC QUANG GRflPHIT V€N Bfli
ThS. PHAM V A N VIET, TS. VU DINH HIEU ThS. D 6 N G O C HOAN - Trwdng Dai hgc Md-Dja chat I dm ngheo khoang san trong qua trinh khai thac
I la mgt vln d l ludn ludn tdn tgi d ede md khai
^ thac khoang san, dae bigt la cac md quang. Tuy jdo dac diem quang, logi khoang san, cdng nghe khai thac khoang san ma he s l ldm ngheo quang se khdc ihau. He so lam ngheo anh hu-dng din rat nhilu cae thdng sd nhu ham luyng quang nguygn khai, tudi thg md, mdc dg thu hdi khi tuyin va dac biet la hieu qua Kinh t l cua dy an. Do dd, bai bdo nay du-a ra phan tich sy anh hu-dng cua lam ngheo tdi higu qua cua dy an khai thdc qugng graphit Ydn Thdi.
1. Tdng quan vd dng dyng, t r u lu-yng va tieu thy qu?ng graphit d Viet Nam va t h l gidi
Graphit (than chi) la mot dgng thu hinh mat dO thip cua nguydn td cacbon. Nguyen t l nay xuat hign ty nhien thi mem khi chgm tay vao va cd mau den.
Doi vdi eac nganh edng nghiep khac nhau thi ydu cdu
±at luyng eua graphit eung khac nhau (Bang 1).
Bang 1. Thanh phin theo mdc chit luang quang tinh graphit (TCVN 4688: 2008)
^""'
*'•• Ten chl tieu i g m luong B c b o n , I(h6ng mmhan
^ " t r o , khong ldn han
p h i t b6c, khong
^ ^ ^ m , khong Ihaiff* lucng tong rstSSnatonhon fcwyri^' dfl??trSn H M y O , 1 ^ 3 B | |
Gr-S 95
4 1 1 0,6
£21 Gr-P
82
17 1 2 1 B 2 0
Mac Gr-T 80
18 2 2 1
Gr-N 79
19 2 2 1
85
m 1
2b«
"
3
i i
Graphit ty nhien ed nhilu hinh thdi: dgng vdy, vd djnh hinh va cue. Graphit cd nhilu ung dgng trong eac nganh cdng nghigp khde nhau nhu sau:
• Chii quet (chdi than) - eho cde dgng co dien trong nha may xi mdng, sat thdp, nhigt dien, dudng slt, eao su, mia dudng...;
• Graphit cho cdc dng dyng co- khi: d l thay t h l mOt sd vdt lidu truyin thing bdi tran, lam tdm dgm graphit bdi tran cho vdnh Id trong edng nghg xi mdng Id ddng tien tiln lam tang tuli thg eua thilt bj Idn gdp nhilu lln;
• Vdt lidu graphit dign eye - diJng trong may xung dien di thay t h l dien eye dong;
<* Khudn mlu Idm bang graphit dae biet cho nhd mdy due lidn tge kim logi quy;
•:• Graphit dOng trong cdng nghidp bdn din, diOn tu;
• Xu hudng tilp theo Id graphit ung dung trong cdng nghg pin lithium-sat. Vdi sy phat U^iln nhanh chdng cua d td su dung rdng rai he thing pin lithium-sit. Hign nay, 2 % eae xe mdi ban du-yc Id xe xang-dign hlu hit trong so dd vdn su dung pin nickel. Dy kiln din nam 2020, cdc logi xe d td xang dien se ehilm 5-^18 % cua tat ca cdc k>gi xe ban ra.
Cdc loai xe nay se duyc trang bj pin lithium-sat, do nhg ban vd cdng suit manh ho-n so vdi pin nickel.
Vdi 70 trigu xe dy doan se duyc ban vao nam 2020, mOt luyng ldn graphit se duyc ydu cdu de san xult pin lithium-sit.
Trd luyng qugng graphit tren toan t h l gidi khoang 389 triOu t i n , trong dd Trung Quic chilm qua nua tru luyng vd san luyng qugng graphit cua todn thd gidi {Bang 2). Theo kit qua tim kilm tiiam do dja chat cho thdy quang graphit Vidt Nam chu ylu ndm trong ddi dut gdy Sdng Hong keo ddi tu Yen Bai d i n Ldo Cai. Ngoai ra cdn mdt luyng khdng Idn ndm d miln Trung nudc ta ehu y l u Id d Hung Nhuyng, Quang Ngdi. Tdng tru luyng qugng graphit udc khoang 23 trigu tdn vd tap trung chu ydu d Ldo Cai ehilm khoang 70 % tdng tru luyng.
C0NGNGHl|PMO,Sti4-2015
Effl. KHOA HOC VA C A N G NGHE MO
Bing 2. Thong, ke ttir luang vi sin lucmg going graphit tren toan the gidi (nguon: internet)
kd :;dc nude 3razi!
i^anada Tung Quoc Jac Triiu Tien knOO Madagascar i^exico
!^ng hod See IThd NhT Ky
^ ^ t n u ^ j ^ k h a i
mam
(10'tan) 2006 113,000
ND 220,000
ND 3,800
960 3,100 14,000
ND 44,000 P98,860
28.3
%
55.2 1.0 0.2 0.8 3.5 11.0 100.0
(ngan tin) 2005
77 30 720 32 130
15 11 10 6 29 1,060
2006 76 30 720 32 120
16 13 5 30 29 1,070
71
%
2.8 67.3
2.9 11.2
1.4 1.2 0.6 2.8 2.7 100.0 Trong khi dd, tieu thy todn cau v l graphit ty nhien da tang tu khogng 600 nghin t i n (nam 2000) tdi 1,2 trieu t i n (nam 2012). Nhu cdu ve graphit dd tdng khoang 5 % mdi nam td 2000 do hien dai hda lien tuc cua Trung QuIe, An DO vd eac nin kinh t l mdi n l i khae ddn d i n tang manh nhu clu cua ede nganh su dgng truyin thing nhu edng nghigp thep vd d td. Trong sd 1,2 tridu t i n graphit san xuat hang ndm cd khoang 40 % Id loai dgng vay ua chudng.
Gid bdn graphit ti-en tiij tiu-dng till gidi lien tyc tang (tinh td nam 2005 din nay dd tdng gdp 3 ldn).
Gid bdn graphit phu thudc vdo kieh thudc vdy va dO tinh khilt vdi cde loai bOt vdy Idn (ludi +80) vd ham luyng cacbon (khoang tren 94% duyc gia cao).
Theo khodng san cdng nghiep nam 2012 thi gia mOt tin graphit giao dich theo hinh thuc FLC CIF tai cac cang chinh d chau Au nhu Bang 3.
Bang 3. Gid bdn graphit trdn thj trwdng quSc te (nguon: www.indniin.com)
t Loai 1 ft Loai 2
• Loai 3 K o a i 4
PpaP
e Loai 6
&s
^ ^ luang
99 - 99,9 94-97
>90 94-97
£90 85-87
! » ^ - 9 7
^ l % 9 0
Kich thu6c vay Lyoi 50 Luoi 80 LucJi 80 Luoi 100+80
Lyoi 100+80
Lu-di 100+80 Ludi 100 Lirdi 100
Gia ban $ -^
4 500-6 000 2 600-3 000 2 000-2 500 2 200-2 500 1.500+2.000 1.500+1.900 2.00O+2.400 1400+1.800
2. Gidi thieu mo quang graphit Yen Thai ^L a. Dpc diem quang va trw Iwgvg
Md graphit Yen Thdi thuOc xa Ydn Thai, huy^
Vdn Yen, tinh Yen Bdi. Khu vyc rat thudn lyi giao thdng, ndm trong didn tich khai tardng khoi 11 ha. Khu vyc thugc vijng nui thdp, ttiuOc c^i Tdy phan Tay Nam dai nui Con Vol va ndm sat trdi sdng Hdng, cac dinh nDi cd dp eao tuydt Qd khoang 130-^150 m vd cd dja hinh thdp ddn td Tgy Bic xulng Ddng Nam. Cac day nui keo ddi theo phuang Tay Bic-Ddng Nam, tren dd thyc vdt khd phat triln. Dja hinh phdn cdt ylu, sudn nui d6c tiung binh 15°^20''.
Tong hyp cde tai lieu thu th^p duyc trong giai dogn tim kilm ti mi vd k i t qua cua giai dogn tha[
dd, da khoanh djnh duyc 3 thdn quang grai trong dign tich tham dd Id than qugng I (TQI), tl qugng II (TQII) va than qugng III (TQIII), trong than quang I va II la cac tiian qugng chieng tr(r luyng chu yeu trong khu vyc tham dd (H.1). ^
H. 1. Mpt cSt dja (^it <^c trung quang gr£
vgc Yen Thai, xa Yen Thdi. huygn Van 1 Yen Bai
Theo k i t qua phe duydt cua HOi ddng danh gid trO- luyng quic gia tiii tong ti^ luyng quang graphit (ca logi quang phong hda va logi qudng chua ptiong hda) thuOc pham vi didn tich khu md ti'nh d (Sip 121+122 Id 2.760 nghin tin, tij-crng ung vdi 357,96 nghin tan cartron graphit
b. Dpc diem ve cong ngh$ khai thac Vdi ddc diem than qudng ndm tren sudn nOi vS dudi moong sau, md dd lya chgn phuo-ng phap t ^ thdc 10 thien. Cdng sudt thilt k l cua md 250.000p qu§ng/ndm. Cdng nghg khai thdc ehu y l u la Wiof n l min, xue bic, vgn tai, thai dd (H.2).
CONG NGHIEP MO. stf 4 - 2 0 1 5
nOivS
p l ooa
1
KHOA HOC VA CONG NGHE MO
_ ^ ^
H.2. Sa di cdng nghg khai thac cho mo graphit khu vwc Yen Thai, xd Yen Thai, huy$n Van Yen, tinh Yen Bai
c. Dpc diem vi cong nghg che biin Cdng nghg tuyen graphit cua md da duyc dp dyng vao thye t l san xult d nhilu nudc. Cdng nghO tuyin chu yeu dp dyng phuo-ng phap tuydn ndi d l lay ra quang tinh cd hdm luyng cacbon tu 80 din 90 %, d l ndng eao ham luyng eac bon trdn 95 % ngudi ta su dgng phuang phdp hda tach de lay ra qugng tinh graphit.
Phuang an tuyen ldy ra qugng tinh graphit cd hdm luyng cac bon trdn 90 %, cdn mOt khau tuyen ehinh, bin khdu tuyin tinh vd mOt khau tuyin vet, sd do hinh H.3 (cd nghiin Igi qudng tinh cua tuyen chinh). Vdi sy d l cdng nghO tuydn tren cho phdp lly ra duyc qugng tinh graphit dat tidu chudn Gr-p theo tidu chuan Vigt Nam, dCing cho san xult pin vd chl biln tiep phge vg xult khdu.
3. Phan tich anh hu-dng he sd lam ngheo qugng tdi hieu qua khai thdc mo lo thien
Lam ngheo qudng Id lam giam chit luyng cua qugng trong qud trinh khai thae do cac nguyen nhdn nhu xOc lan dit dd vao qugng, hoae xuc lln qudng khdng dam bao tidu chudn.
Ty le tdm nghdo du-yc xdc ^nh tivc tilp dya ti-dn ty sd gij>a dit da hogc quang phi tidu chudn vd qugng nguyen khai khai thdc duyc, Uieo cdng tilde:
r = ^ . 1 0 0 % . (1) Qk
Trong dd: Qd - Khii luyng d i t da ldn vdo ho§c qudng phi tieu chudn lan vao, t i n ; Qk - Khdi luyng qugng nguyen khai khai thdc duyc, t i n
Ngodi ra, ty lg Idm nghdo cung cd t h l tinh toan gidn tilp thdng qua ham luyng thanh phdn ed ieh (TPCI) chua trong qudng. theo cdng thdc (2).
r = r = - ^ (2) a-a"
Trong dd; a - Hdm luyng TPCI chda ti-yng qudng trij- luyng, %; a ' - Hdm luyng TPCI chda trong qu^ng nguydn khai. %; a'- Hdm luyng TPCI chda ti-ong qudng phi tieu chuin lan vdo, %.
H.3. Sa do cdng nghg tuyin di liy ra qupng tinh graphit cd hdm Iwang cacbon tren 90 % Ldm ngheo qudng la mOt trong nhung nhdn t l anh hudng d i n higu qua kinh t l cua dy dn khai thdc md. Cho dij mdc dO ldm nghdo nhd d i n dau cung Idm giam higu qua cua dy dn khai thdc.
Ngdy nay, do ddu tu tien vd thdi gian khdng hieu qua cho nghien euu vd cdn thilu phuo-ng phap djnh lu-yng md ed t h l su dyng. Thay vi tinh toan mdc dO ldm nghdo trong nghidn cdu khai thac md, chOng ta thudng gia djnh mdc dO ldm nghdo Chung chung nhu 5 % do! vdi khodng sdng dang khii vd 10 % d l i vdi khodng sdng dang via.
Trong khi nhung so ligu ndy Id r i t t i t cho giai dogn nghien cuu khai thdc ban d i u bdi vi nd khdng c i n dua ra xem xdt v l n de phdc tap. He s l Idm ngheo thay doi trong cdc ting vd cdc vCing khdc nhau cua mOt mo. D i l u ndy Id do thay d l i v l phdn b l ham luyng vd hinh dgng thdn qu$ng. HO s l ndy cdn thay d l i theo gid trj khodng san. Do viy, eln ddm bao nhung thay d l i ndy d l duyc dua vdo tinh todn khi thiet k l vd ddnh gid mOt md.
G0NGNGHl£PMi.Stf4-2015
^ ^ _
KHOA HOC VA CONG N G H | MO Lam ngheo quang ddn den tdng cae chi phi sanxult d xudng tuydn do tang khoi luyng khoang san dua tdi nhd may. Them vao dd anh hudng tryc tilp eua lam ngheo trong ngln hgn la gia tri thu duyc cua md, cdn trong dilu kien lau ddi Idm ngheo qugng giam gia trj todn bO dy an md do anh hudng tdi mgt s l nhan t l khac. Vi dy nhu keo dai tuli thg md do giam khdi luyng quang thye t l dua vdo nhd may tuyin vd cdn giam hdm luyng quang dua vao nha may tuyin so vdi thilt k l ban ddu.
Trong hdu hit cac trudng hyp duyc ghi nhdn hdm luyng dua vdo nha may tuyin thdp ddng nghTa vdi vdi viec mdc dd thu hli khi tuyin cung se thip.
•Han nua, lam ngheo quang cdn Idm tang hdm luyng bien do tang ham luyng edng nghiep t l i thilu eua toan md.
Trong vai trudng hyp, tao dilu kign t i t v l higu qua kinh t l , eae nha quan ly md thudng cd xu hudng khai thdc vdi san lu-yng cao, ddng nghTa vdi hgn chl khai thac chgn Igc vd gia tang lam ngheo. Tuy nhien, eye ky khd d l giam chi phi tu Idm ngheo trong thyc t l khai thdc md va ty lg lam ngheo trgng thyc t l Id khdng the tranh khoi trong hau hit eac hoat dOng khai thdc md. Mae diJ khd ed t h l tranh khdi lam ngheo trong khai thac quang nhu-ng chung ta ed t h l ddnh gid vd dieu khiln nd.
Bing vige tim hilu t i t nguon goc gay ra Idm ngheo vd cd k l hoaeh hyp ly, chCing ta cd t h l dilu khiln Idm giam muc dO lam nghdo.
Lam ngheo quang thay ddi theo cde md khac nhau dya trdn cac dae trung khodng sang, cdng nghd khai thac vd hdm luyng bien. Vi dy, hinh dgng khoang sdng, chilu eao tang, kieh thudc thiet bj vd eac dilu kidn thj trudng se anh hudng din mdc Idm ngheo trong md.
4. Nghien edu anh hu-dng cua lam ngheo d i n hiedqua d y an khai thac grapit Yen Thai
a. Anh hwdng cua lam ngheo quang ton ham Iwang quang nguyen khai
Md graphit khu vyc Yen Thdi dd duyc tham do chi tilt d l dam bao lap dy dn dau tu khai thac md, vdi hdm luyng quang tru luyng trung binh toan md la 13 %. Trong hoat dOng khai thde qugng graphit Yen Thai su dyng cdng nghg khai thac gdm khoan n l min, xuc bdc, vdn tai. Do vgy, trong qua trinh khai thac se khdng tranh duyc lam ngheo qugng.
Tuy thuOe vdo edng nghg khai thac tai mo se cd muc dO ldm ngheo khdc nhau. Hidn tuyng Iam giam ehit luyng qudng nguyen khai se giam tuy thude vao mde do Idm ngheo qu^ng tgi md theo cdng thue:
a'^=(1-r)a+r.a" (3) D l danh gia dilu kidn anh hudng Idn nhit vd
CONG NGHIEP mo, sd 4-2015
Idm giam ehdt iuyng quang nguyen khai, xdt Q^
dd lan vdo qugng vd hdm luyng qugng phi c6ng nghigp la 0 %.
a'=[(1-r).a]. (4) Trong do: a - Ham luyng cacbon trong qu|ng
graphit tru luyng, %; a" - Ham luyng cacbon trong qugng graphit nguyen khai, %; r - Ti lg lam ngheo quang graphit thyc t l trong qua trinh khai thdc. %.
Dd ddnh gtd anh hudng cua ti lg Idm ngheo qugng d i n sy thay ddi ham luyng cacbon trong quang graphit Yen Thai, tac gia thay doi ti lg ifm ngheo vdi sy gia tang 2 % tu 0 din 10 %. Kit q|i tinh todn t h l hign ey t h l tren Bang 4 vd H.4. P
S^ng 4. Thay dSi cua ham Iwang qu§ng graphl Yen Thai nguydn khai vdi ti ie ham ngheo. , , ^ J
Ty 1$ l^m ngh6o,%
0 2 4 6 8 10
Ham lugng \ a, % ?
13 13 1 13 13 13 f 13
iEiiiiUl»i Utea
.s^Ham li/ping a
fngh^o, % H.4. Moi quan hi giua ham luang going g
Yin Thil nguyen khai va tlli Hm nghio ' b. Anh humg dia Hm ngheo quang tdi tuoi thg n Trong hoat dgng khai thac mo d Vi§t Nam, cfinT suit mo thu&ng la mot thang s6 a l kh6ng chi m*9 dp khai thSc h^ng nam cua mo. Nhung do hi$n tugng ISm ngheo qu|ng trong qui trinh khai tiiSS nen khoi lugng quang dam bao chit lugng lly ISi
KHOA HOC VA CONG NGHi M O
_ ^ ^
LT long ddt lgi jt han so vdi cdng suit khai thdc cua nd. Do vay, tudi thg md trong luc thilt k l va thye t l logt dgng cua md se cd sy khac nhau phg thuOc 'do mdc dp lam ngheo cua md. Ddi vdi mo qugng iraphit Yen Thai, thi cdng sudt md la 250.000 an/nam quang graphit nguyen khai. Tru luyng
;u|ng_ la 2760 nghin t i n . Nhu vay, tudi thg md thay loi thd hign nhu H.5.
—Tu6l th ? m 6
-,r_., ^_ T J l § I S m n g h e o , % -Jc""^'- -
H.5. Thi hign sw thay doi tuoi tho md vdi tiig Idm nghdo dmd qupng graphit Yen Thai Nhu vay, td d l thi thdy rd rang rdng, khi khai hdc vdl hO sd lam ngheo thay doi tu 0 % tdi 10 % hdi gian khai thdc hit quang tang td 11 nam tdi 12,3 nam. Nlu md duyc d p .phep khai thae trong II nam thl phdn khdi luyng bj t i n thdt khdng khai hdc duyc se Id 25.000 t i n .
c. Anh hwdng cua iam ngheo quang tdi mu'c '.hu hoi qupng khi tuyin
Qu§ng graphit khu vyc Yen Thai muln duyc di idu thy phai trai qua qua trinh tuyin d l ndng eao iam luyng quang tdi mue do yeu cdu tCiy thuge /do nhu edu su dung. IVld tiln hanh phdn Uch kha uyln de danh gia kha ndng tuyin d l i vdi qugng jraphit khu vye Ydn Thdi. Qua qua trinh tuyin iu§ng graphit cd the nang Idn 90 % vdi mgt khau uyln ehinh, bin khau tuyin tinh vd 1 khdu tuyiri
^dt vdi thye thu 58,98 %. Dd danh gid sy anh ludng cua he so lam ngheo quang tdi muc thu hdi lu^ng graphit khi tuyin vdi ty Id Idm ngheo thay Jli td 0 % d i n 10 %, t h l hign cy t h l qua H.6.
d. Anh hwdng cua tam ngheo qupng tdi hieu jua dy an
D l i vdi cdc dy dn dau tu ndi chung va dy dn ilu tu khai thac khodng san ndi rieng, tru-dc khi iln hdnh ddu tu, cac dan vj md thudng phai ddnh lid hi$u qua boat dOng khai thdc trong tuang lai d l ,pa chgn phuang an dau tu hyp ly. MOt trong ihung ehi sd dung d l ddnh gia hidu qua cua dy an fd Id NPV (Net Present Value). Ddy la mgt gid trj
tdng hyp danh gid higu qua cua dy an tu eae gia tri kinh t l ky thuat cua md MOt trong nhung eae y l u t l anh hudng din higu qua cua dy an khai thdc md dd Id mue dO ldm nghdo quang trong qua trinh khai thac md. Danh gia sy anh hudng eua hO so Idm ngheo din hieu qua dy an khai thac graphit Yen Thai, tac gia tiln hanh xdc djnh gid tri NPV theo hg s l Idm ngheo thay ddi tu 0 % din 10 %. Kit qua Unh todn duyc the hien cu t h l tgi H.7 va H.8.
^
"?,
o 7 . 6 •
7.2
—^r-VILTcthu i6i, gt
*«tife ^TJ*Bni.gheo,%
H.6. Thi hidn mSi quan he gida muc thu hoi quang graphit Yen Thdi khi tuyen va ti le Idm nghdo qupng
60.000 ao.ooo
dtt
H. 7. Gii tli hiin tm thi/c ciia mi gmphit Yen Thii
^ 30.000
•g 20,000 1 10.000 • E
6 °
'
• 1 -•— 1^
• •
w •
0
1 •
• • •
™ . M , M , 2 a 6 • 1 M , 8
m
JOH.8. Gii tri NPV raia md graphit Yin Thii thay dol theo tlli lim ngheo
CdNG NGHIEP MO, SO 4 - 2 0 1 5
^^_
KHOA HOC VA CONG NGH| M O5. Ket tudn
• Quang graphit la mdt loai khoang san duyc su dyng cho nhilu nganh cdng nghiep, dac bidt la pin eho eae loai d td dien ti'ong tuang lai. Tru iuyng quang graphit tren t h l gidi tuang dli nhd so vdi cae loai khoang san khde.
• Quang graphit khu vye Yen Thai, xa Yen Thai, huyen Van Yen, tinh Yen Bai dap ung tnJ luyng cdng nghigp vd cac dilu kign khdc dam bao khai thac bdng cdng nghe khai thac 10 thien ed hiOu qua vdi cdng nghe khai thac ehinh khoan-nl min, xuc bde, van tai.
<• Trong qua trinh khai thac md qugng graphit khu vyc Yen Thai se khdng trdnh khoi lam ngheo quang. Tuy vao mdc do Idm ngheo cu till thi md se ed hieu qua kinh t l Id khdc nhau. Do dd, eln nghidn euu tiiem v l vdn d l Idm ngheo quang d l xde dinh duyc mOt ti Id tin thit lam ngheo hyp ly vdi cdng nghd khai thae chl biln eua md su dyng.n
TAI LIEU THAM K H A O
1. Phgm Van Viet, Vu Dinh Hllu vd nnk. Bdo cao dy an: "Dy an dau tu xdy dyng edng trinh khai thae md quang graphit khu vyc Yen Thdi, xd Ydn Thai, huyen Van Yen Tlnh Ydn Bai". 2012.
2. Ho ST Giao. Thilt k l md 10 ttiien, Nhd xual ban Gido dye. Hd Ngi. 1999.
3. Tran Manh Xuan. Cde qua trinh san xult trfin md 10 thien. Hd Ndi. 1997.
4. Trdn Mgnh Xudn. Quy trinh cdng nghg vd tw sd thilt k l md Id thien. Ha Ndi. 1991.
5. Trdn Manh Xudn. Khai thde qugng blr^
phuang phdp 10 thien. Ha NOi. 2000.
Ngwdi bien tap: Vd Trgng Hung ^
Mineral dilution in mining operation has been an existed issue in mines, especially ore mines. Depending on ore features, ore kinds and mining technologies, the dilution rates are various. The dilution rate affects to a lot of parameters like ore grade, mining life-span, the recover rate of processing and especially the econimic effect of mining project. Therefore, the paper shows the affection of the dilution to exploiting effect of Yen Thai graphite project.
NHOM CAC HE KHE NUTT...
(nip theo trang 111)
Ldi cam an. Chfing tdi xin ehan thanh cam an ngai Thierry Verdel, Gido su, tiifdng ekip GOR, phdng tiii nghigm GeoRessources, Ecole des Mines de Nancy, Universite de Lorraine, dd h i ti'y vd tu vln giiJp ehung tdi thye hien nghien cdu ndy.n
TAI LIEU THAM KHAO
1. S. Priest. Discontinuity analysis for rock engineering. Chapman & Hall, 1993, p. 473.
2. M.A. Mahtab and T.M. Yegulalp. A Rejection Criterion For Definition Of Clusters In Orientation Data. Am. Rock Mech. Assoc, vol. The 23rdU, p. 8.1982.
3. Y.N. Andrev/, I.J. Michael and Y. Weiss. On spectral clustering: analysis and an algoritiim. Adv.
Neural Inf. Process. SysL, vol. 14, no. Cambridge MA: Mit Press, pp. 849-856, 2002.
4. D. Heliot. Generating a blocky rock mass. Int.
J. Rock Mech. Min. Sci. Geomech. Abstr., vol. 25, no. 3, pp. 127-138,1988.
5. V. Merrien-Soukatchoff, T. Korini and A.
Tlioraval. Use of an Integrated Discrete Fracture Network Code for Storfiastic Stebility Analyses of Fractured Rock Masses. Roek Mech. Rock Eng., Mar. 2011.
C6NGNGHllPM0.sd4-2015
Ngwdi bien tpp: Ho SJ Giao
