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CNM ''''M NGANH KHAI THAC MO LO THIEN CAC PHUUNG PHAP XAC DjNH HAM LUONG DIEN TOI UU Vdl CAC MO HINH TO CUOfC KHAI THAC MO LO THIEN ThS NGUYEN ANH TUAN Trw&ng Dai hgc Mo Dja chit 1 Khai quat chung Trong[.]
CNM 'M NGANH KHAI THAC MO LO THIEN CAC PHUUNG PHAP XAC DjNH HAM LUONG DIEN TOI UU Vdl CAC MO HINH TO CUOfC KHAI THAC MO LO THIEN ThS NGUYEN ANH TUAN Trw&ng Dai hgc Mo-Dja chit Khai quat chung Trong khai thac md Id thien cd rIt nhiiu ly thuylt t i i uu gia tri HLB thdng qua ham muc tieu ting Igi nhuan cua md Idn nhit eac giai doan san xult.Gia tri HLB duge dCing d l phan biet giua quang va da bdc pham md quang Id thien Ben canh dd, edng nghe c h i biln, luyen kim cang anh hudng sau rdng tdi eae md hinh he thing t l chuc khai thae md quang Id thien Cae md hinh t l hgp md quang Id thien nhu "md", "mdtuyln", "md-tuyln-luyen" eang p h i biln d nude ta Tu eae t l hgp nay, viee xae dinh HLB, khii quang nguyen khai dam bao he thing md van hanh hieu qua la yeu c l u rIt quan trpng Khoang san ed du ham lugng d l khai thae, c h i biln va luyen hieu qua dugc gpi la HLB theo dilu kien kinh tl-ky thuat Vdi dac dilm cdng nghe khai thae quang Id thien tren t h i gidi hien thi gia tri ham lugng quang t i i uu se quyit djnh tinh hieu qua eua du an Trong pham vi bien gidi md thi quy luat phan b l ham lugng vdi tru lugng quang cd xu t h i theo biiu d l hinh H.1 AQc, tan dua vao khai thae va c h i biln hieu qua HLB cd t h i thay d i i theo giai doan va phu thupe vao cac y l u t l dia chit, kinh t l va ky thuat cua md 2.1 Xac djnh HLB theo phu'ang phap c l diln Theo phuang phap e l diln, HLB duge xae djnh blng tru lugng quang ed du ham lugng khai thae, ehi biln va luyen kim hieu qua pham vi bien gidi md quang Id thien a Xac djnh HLB theo dilu kien bien gid'i khai thac HLB theo dilu kien xac dinh bien gidi md quang Id thien dugc djnh nghTa nhu ham lugng gidi han can blng giua ehi phi khai thae, ehi biln, luyen va ehi phi djch vu vdi ting gia tri cua khii lugng kim loai thu h i i dugc ban ngoai thj trudng Gia tri HLB theo dilu kien bien gidi (gHLB_BG) xac djnh theo edng thLFC (1): ,, c +m gH^^-^^^P + F + s ) y ' ' ^ ^ ' ' ^'^ Trong dd: c - Chi phi c h i biln, d/t; m - Gia khai thae mpt tin qugng, d/t; P - Gia ban quang, d/t; F - Chi phi luyen mpt t i n quang, d/t; s - Chi phi dich vu eho mpt t i n quang, d/t; y - He s l thu hii quang, dvtp Vay, HLB xac djnh theo dilu kien bien gidi md duge su dung d l dam bao lugng khoang san ed gia tri khdng bj t i n thIt (ly thuylt duge Crng dung cae "thuat toan hinh ndn dpng" va "quy hoach dpng Learehs-Grossmann" xac djnh bien gidi md) b Xac djnh HLB theo dilu kien c h i biln Gia tri HLB theo dilu kien c h i biln (gHLB_NT) xae dinh theo cdng thuc (2): gHLB_NT = ^ p ^ ; ^ ^ ) y , d v h l H Sa dac diem phan bd ham lwgng (g) vdi tnr lwgng quang (Q) bien gidi md quang Id thien Cac phu'ang phap xac djnh HLB Theo quan niem c l diln, HLB la gia tri ham lugng trung binh nhd nhit cua khoang san ed t h i CONG NGHIEP MO SO - (2) Tu biiu thuc (2), HLB theo dilu kien c h i biln thi chi phi khai thac va cac y l u t l kinh tl-ky thuat lam gia se khdng duge tinh d i n Oo dd, nlu ting chi phi khai thac, ehi biln, luyen va bao gdm ca djnh phi d l khai thae mpt t i n quang nguyen khai nam ed ham lugng cao han HLB tinh chpn thi phuang an se mang lai hieu qua kinh t l cho md HLB theo dilu kien ehi biin duge su dung d l dam bao khii lugng khoang san KY NIEM 45 NAM DAO TAO NGANH KHAI THAC MO LO THIEN nguyen khai dugc khai thae va dua v l nha may tuyin ed gia tri ham lugng nIm pham vi eho phep Trong dilu kien hien nay, da s l cac md tiin hanh thiit k l d i u su dung phuang an HLB tren ea sd phan tieh gia tri kinh t l gidi han ma tai dd md cd Igi nhuan Idn nhit; eae md su dung phuang an HLB Idn han gia tri HLB theo dilu kien kinh t l d giai doan diu khai thac; eac md d i u ung dung ham muc tieu NPV -^ max cho t i t ca eac md hinh md k l ca eac dii tugng md cd kha nang tru lugng, ham lugng phan b l khdng I n djnh Tu phan tich tren ta thIy nhung han c h i ea ban la gia tri HLB dugc tinh gia tri Igi nhuan eua md Idn nhit nhung ap dung eho t i t ca eac giai doan san xuat; gia tri HLB coi nhu hing s l k l ca ehi phi san xult, gia quang ludn biln ddng thdi gian khai thac cua md; qua trinh xae dinh HLB chua quan tam tdi su phan b l ham lugng quang than khoang sang 2.2 Xac djnh HLB theo cac mo hinh to chiFC khai thac mo khac Cac md hinh t l chuc khai thac quang Id thien nhu "mo", "md-tuyin", "md-tuyln-luyen" cang phi biln d nude ta nhu d u phat triln eua nganh cdng nghiep mo va tinh nang dpng cua thj trudng khoang san Do dd, gia tri HLB se ed xu t h i dugc xac djnh theo nhiiu quan dilm khae nham tii uu hoa kha nang Igi nhuan cua cae md hinh md Vi thi, phuang an HLB I n djnh tung giai doan hoac giam d i n theo thdi gian khai thac md se tilp tuc duge nghien CLPU van dung mpt each linh hoat eho cac md hinh md thich hgp a Xac djnh HLB I n djnh cac giai doan khai thac nhit djnh Ting quat thi Igi nhuan hang nam eua md quang lp thien dugc xac dinh theo biiu thCpc (3) Pr = ( P - s ) Q , - Q , c - Q ^ m , d (3) Trong dd: Qm- khii lugng quang nguyen khai hang nam, tin; Qc- khii lugng quang c h i biln nam, tin; Qr khii lugng kim loai thu hii sau luyen, tin Khi dd, gia tri hien tai thuc cua du an khai thac md Id thien duge xae djnh theo biiu thue (4) Pr (P-s)Q.-Q,.e-Q,.m (1 + d) ^^^ (1 + d)' Vdi: i - Thdi gian khai thac md d cac nam tuang LPng (i = 1, , N vdi N - Tuii thp eua md, nam) ^ Nhu vay, gia HLB xac djnh theo phuang phap c l diln khdng phai lue nao md eung thoa man ham muc tieu NPV Idn n h i t Phuang an ky thuat chpn ed ham lugng cao han HLB gidi han v l kinh t l CNM dugc su dyng nhung nam d i u khai thae nham tang tie dp thu hii v l n , sau dd su dung HLB gidi han nh&ng giai doan mudn han Md hinh xae djnh HLB d l xult theo cae phuang an bien gidi md d cac giai doan t h i hien tren hinh H.2 Vdi mpt md quang id thien, phuang an HLB theo Ijch k l hoach duge tinh chpn nhu sau: Trong nam d i u eua du an md, gia tri (gHLs.Ni) duac xae dinh: C + D + Mp +fa , (5) 9HLB NT dvhl (P + F + ^—^ s).y TCr nam thCp tdi nam 10 cua du an md, gia tri (gHLB_NT) duge xae djnh: c + D + f , , ,„, - - - =(P7F7^'^^'' (') H.2 Mat cit cae phwang an chidu sau day md vdi cae HLB khae nhau; gHLB_i, gHLB_2, • gHLBj,. gHLB.n- cac phuong an HLB 1, 2, , i, n TLP nam thCp 11 tdi cac nam sau dd cua du an md, gia tri (gHLB_NT) dugc xac djnh: c + f= -, dvhl (7) QHLB NT (P + F + s).y Trong dd: - Gia giam nhung nam d i u thuc hien du an, d; Mpr- Phuang an Igi nhuan nhd nhit ed t h i cua du an chpn, d; fa - Chi phi c l djnh hang nam cua md, d Nhu vay, gia tri HLB duge xae djnh nam d i u md se cd Igi nhuan nhd nhit Do edn khd khan giai doan d i u khai thae, su giam gia khai thac dugc tinh d i n trong 10 nam d i u khai thae eua du an md b Xac djnh HLB nang dong phu hgp vo'i cac md hinh t l hgp mo lp thien khac Xu hudng tilp can xac djnh HLB giam d i n toan bd thdi gian khai thac md se mang lai gia trj NPV cao han so vdi phuang an HLB c l djnh Bai toan dat la lam t h i nao d l xac djnh gia tri HLB t h i thu dugc gia tri NPV la cao nhit mpt thdi gian t i n tai cua md Ca sd ly thuylt xac dinh CONG NGHIEP MO SO - KY NIEM 45 NAM DAO TAO NGANH KHAI THAC MO LO THIEN HLB vdi gia tri NPV Idn nhit bao g i m djnh phi nhung khdng tinh tdi su biln ddng eac ddng tiin tiin hanh du an vi HLB dugc tinh d mdt thdi dilm nhit djnh Theo quan dilm tren, tac gia d l xult su dung cdng thLPC tinh gia tri HLB eua GS.F.K Lane [1] ham muc tieu NPV Idn nhit vdi dilu kien c h i biln dugc xae dinh theo (8) Ta cd : v=V-Vq=Pr-V.d.T, d C^) Biiu thLPC (14) cho thIy ca hdi v l ehi phi khai thae, gia quang tac ddng lam giam gia tri HLB tuang lai ma ham lugng khoang san cao van cdn bien gidi md Khi dd, Igi nhuan hang nam (v) duge xac dinh theo (15) v=(P-r-s).QrC.Qc-m.Qm-f.T-V.d.T, d (15) Trong dd: P - Gia ban mdt t i n quang thuang phlm, d; r - Chi phi tilp thj cho mpt t i n quang gHLB_NT(i) = P ^ < J v h l (8) thuang phlm, d; s - Chi phi ban quang tinh eho mpt t i n quang thuang phlm, d; e - Chi phi chi Trong dd: gHLB_NT(i)- phuang an HLB duge su biln mdt t i n quang, d; m - Chi phi khai thac mpt dung nam khai thac thu i, % (dvhl); Fr gia tri t i n quang nguyen khai, d; f - Djnh phi hang nam triln vpng (ea hpi) eua t i n quang nam khai (ehi phi eho phep hang nam) cua md, d; T - Thdi thae thu i, dugc xac djnh: gian d n thiit d l khai thae, c h i biln va luyen khii A NPVi lugng quang nguyen khai Qm, nam (9) = d -, d Dung tren quan dilm ed nhiiu md hinh t l chLPC khai thac md quang Id thien, md hinh ting quat bao (10) f=:^ gdm: cae qua trinh san xult tren md Id thien khai Vdi: d c- Gia tri ehilt khau; NPV - Gia tri NPV cua thae quang nguyen khai, qua trinh nghiln-tuyin d l ddng tiin tuang lai eua nam thu (i) eho tdi ehi biln khoang san nguyen khai va qua trinh kit thuc khai thac md, d; fa- ehi phi e l dinh luyen kim cho san phlm tinh quang cull cung * Khi san lugng nguyen khai md Id thien bj han hang nam cua md, d chi, anh hudng d i n t l hgp md: Gia tri NPV Idn nhit: Khi dd lugng thdi gian khai thac dam bao san NPV = i P r - ^ d (11) lugng yeu cau, T=Qm/M (16) i=i (1 + d) Lgi nhuan cua md duge xac djnh theo cong Dilu kien: Q^{\) < M; Qc(i) < C; Qr(i) < R vdi i = thLPC (17) v a d i thj hinh 1, ,N Trong dd: Qm - Khii lugng quang nguyen khai nam, tin; Qc - Khii lugng quang ehi biln nam, t i n ; Qr - Khii lugng kim loai thu h i i nam, tin; M - Kha nang san lugng cua md hang nam, tin; C - Cdng suit c h i biln nam, tin; R - Cdng suit luyen kim nam, tin Ca sd d l ehi phi cua du an md, gia quang cho phep giam gia tri HLB qua trinh khai thae duge xae djnh nhu sau Nlu gia su gpi cae gia tri nhu sau: V - Gia tri hien tai thue Idn nhit ed t h i tuang lai mang lai qua trinh khai thae eua du an khai thae quang Id thien, d; Pr - Gia tri Igi nhuan cua md mang lai khai thac khii lugng quang Qm, d; Vq - Gia tri hien tai thue Idn nhit ed t h i ed tuang lai sau khai thac khii lugng Qm quang Khi dd: v=(V-Vq),d (12) Vdi V - Gia tri hien tai thuc tang them dat dugc khai thac gin khii lugng quang Qm Tu dd, ta cd: V= Pr + V, , f=i>V.(1 + d)^=(Pr + V-) (1 + d)^ (13) q' Nlu i kha nhd thi: (1 + d)' = (1 + d T) :^ V.(1 +d.T)=Pr+Vq hay (V-Vq)=(Pr-V.d.T); CONG NGHIEP MO SO - Vm=(P-r-s).QrC.Qc ^^^-^ H.3 Sa dd moi quan he giira Igi nhuan vdi HLB Khi dd, gia tri HLB theo dilu kien xae djnh bien gidi md dugc xae djnh: (18) (P-r-s).y Vdi y - He s l thu hii quang, dvtp • Khi cdng suit c h i biln cua md anh hudng tdi t l hgp khai thae md: Khi dd thdi gian d n thiit c h i biln khii lugng quang nguyen khai nam Qc: T =^ (19) KY NIEM 45 NAM DAO TAO NGANH KHAI THAC MO LO THIEN Lgi nhuan eua md trudng hgp duge xac dinh theo edng thuc (20) f + d.V (20) Qc-m.Qm, d Vc=(P-r-s).Qr- c + - CNM ,gmr=R/M=f(g) Gia trj HLB theo dilu kien che bien dugc xac dinh theo biiu thue (21) f + d.V c+ (21) •, dvhl ^'" ( P - r - s ) y •:• Khi nang suit khau luyen kim la nhd nhit he thing md hinh : Thdi gian d n thiit d l luyen hit khii lugng quang tinh Qn (22) R Lgi nhuan eua md du/gc xac djnh theo eong thCpc (23) f + d.V" Qrc- Qcm.Qm d (23) Vc=(P-r-s- e + Gia tri HLB theo dilu kien luyen kim duge xac djnh theo cdng thu'c: Cae biiu thCre (18), (21) va (24) xac djnh gia tri HLB vdi cae dilu kien ky thuat edng nghe tuang LPng vdi cae dilu kien khai thac, c h i biln va tuyin tuang ung he thing md hinh md Khi can blng HLB md hinh md "mdtuyln", ty s l giua edng suit c h i biln vdi san lugng nguyen khai eua md, ky hieu gmc, % (gmc=C/M, %) duac xac dinh theo d l thi hinh H.4 H.5 Sa dd can bing xae dinh HLB giwa edng suit luyen kim (R) vdi san Iwgng nguyen khai (M) cCia md loai theo sw phan bd tieh luy ham Iwgng quang gdc Khi can blng HLB md hinh md "mdluyen", ty s l giua cdng suit eua nha may luyen kim vdi san lugng nguyen khai cua md, ky hieu gmr> % (gmr=R/M, %), xae djnh theo d l thj hinh Khi can blng HLB he thing md "tuylnluyen", ty s l giua cdng suit cua nha may luyen kim vdi nha may ehi biln, ky hieu gcr, % (gcr=R/C, %) xae djnh theo biiu d l hinh Gia tri HLB theo dilu kien kinh t l d tCpng khau edng nghe he thing md dugc xae djnh theo eae edng thue (25), (26) va (27) •:• HLB theo dilu kien xac djnh bien gidi md lai nhuan cua md V=0 (25) dvhl (%) (P-s).y •:• HLB theo dilu kien c h i biln Igi nhuan cua md V=0 d + d.V 9n 'gn.c=C/]VI=f(g) g,^ ^ ,dvhl(%) (26) (P-s).y • HLB theo dilu kien luyen kim Igi nhuan cua md V=0 (27) f + d.V P-s y R Kit qua khao sat bai toan eua mpt s l md quang ding tren t h i gidi va d Viet Nam cho thIy vdi Igi nhuan cua md hang nam V=0 va V^t thi m i i quan he giua HLB vdi gia tri Igi nhuan cua md dilu kien xae djnh bien gidi md, c h i biln va tuyin khoang nhu d l thj hinh H.7 Qr = g, % (dvhl) H.4 Sa dd can bing xae dinh HLB giCra edng suit ehe bidn (C) vdi san Iwgng nguyen khai (M) eua md theo sw phan bd tich luy ham Iwgng quang gdc ^ ^ T T T ^ dvhl(%) CONG NGHIEP MO SO - CNM KY NIEM 45 NAM DAO TAO NGANH KHAI THAC MO LQ THIEN 'kv.d y, dvtp -100 0.1 0.2 0.3 0.4 0.5 0.6 ^if^ 0g gHi.e.% Chu thick -200 - * - • -X- •VC ViingkMthi •vr -300 g, »/o (dvhl) H.6 Sa dd can bang HLB giOa giCra edng suat luyen kim (R) vdi chi bidn (C) theo sw phan bd tich luy ham lwgng quang gdc H Sa dd xae djnh HLB tdi wu (gtsi wu) vdi cac phwang an Igi nhuan twang wng vdi cae md hinh md khae b) a) ^nnc 'mc ,1 Qm 1 9r gc neug mc'^gm G mc - 9rr 9m 9r Gmc=gcneug^