TapchtDIArilAT l„^., ft,,,^ na i.Toin^j ,, T^ ^
NGHIEN CVV DINH LlTONG CAC THONG SO PHAN ANH CHAT LlTONG QUANG: Vf DU CHO THAN BAUXIT
TRONG v o PHONG HOA LATERIT
TRirONG XUAN LUAN'. DU'ONG THI TAM'. LE VAN LU'ONQ-' 'Trudngpai hgc M6-Bla dial Dang Ngac. Tir Liem. Ha Ngi.
' Van phong Hoi ding Danh gid Trir luong Khodng sdn. 6 Pham Ngfi l^. Ha Noi Tim lit: Died CO sa cbo cdng tdc thdm dd khodng sdn ligp Iv. vdn di cdt ldi li m tiep can gdn dung nhdt linh bien ddi cdc thong sd phdn dnh chdt lugng qugng Batg cdc phmmg phdp truyen thdng chung la chi co Ihi hiiu dugc mia- dg bitn dgt md khdng biet dugc dgc tinh vd cdu true ciia sw biin ddi cdc Ihdng sd dd. Vdi su trg giiip cua cdc hdm cdu tnic trong dia thing ki. cdc tdc gid bdi bdo dd nghiin cuu dinh lugnf khdng gian cdc thdng sd dgc tnmg cbo chdt lugng qudng rd co va, tro gdy khd de cho edng uie thdm dd dd nhgn thuc dugc todn dien tlnh biin dd, cic thong so nghien am Irong khong gian timg thdn khodng vd nhu vgy. gdp nhdn biin dg, hoa cang Idc ddnh gid cdc tu khodng Cdc tdc gia dd su dtfng cdc Ihdng tm li, than bmeal ngng ddi phong hda laleril diin hinh cua „,gt ig khodng cho cdc iinl, loancuammh Cdc kel qud nghien ahl cdc hgp phdn AljOj. SIO, cho phep nhgn dinhca 2 Ihong so phdn bo gdn chudn. AhO, thugc logi biin ddi rdi ddng diu-
?' '™ t ' - * " ? f "• "<^ " * « " '•*™^ ^-S ' ' ^ tinh biin ddi khdc nhatc ,lmh phmS,0,b,ln dd, phuc tgp hon Alfi, vd cd biiu hien ctm linh dl l,ud„g khu vuc
IZT'i. u- ^'" " """ ' * " * " '''"'• * " * ? " " ' " * * "'dng ludi ihdm do pnu hgp cho thdn qugng.
khoang vat khac nhu ilmenit, limonit, thach anh, chlorit cd hdm lugng nhd,...
Ham lugng tiimg binh cic thanh phin chinh: AI2O3 = 51,40%; SiO; = 3.40%;
FejOj = 15,23%; TiO; = 2,50%; MKN = 26,01%; modul silic - 13,13%;...Iiam lugng cac chit cd hai nhu P20i = 0.17%;
SO3 = 0,02%;... Cac nguyen Id cd ich di kem cd ham lugng khdng dang kd. Trii lugng Uian quang chpn nghien ciiu thupc loai cd quy md trung binh.
I.GIdlTHI$u
Tiep theo mpt sd bai bao gioi Uiieu vd phuong phap dja thong kd trong nghien cira cac khoa hpc dja chk. ttong bai bao nay, Chung tdi gioi thieu kdl qua nghien Clhi ve Uian bauxit kha didn hinh, phan bd trong ddi phong hoa latent, mdt loai hinh rat phd bien 0 nuoc ta. Than bauxite duoc chpn nghien cim la san phim phong hoa lu cac da bazan ciia he ling Tue Trung (BNrQi „). Than quang dat chi tieu cdng nghifp cd dang keo dai phuong bic-nam
™ chieu dai 6,5 km, chidu rdng dao dgng 0,5-2,0 km. Chieu day ttmn quang cdng nghiep dao dpng 1,0-7,0 m. Bauxit chd yeu d dang bd rdi, dang manh, xi, gdc eanh, dang kel vdn; it hon cd bauxit dang gia cau, tang. Thanh phin khoang vai ttong quang nguyen khai chu ydu la eibsil (tijing binh 58%); kaolinit-haloysit (TB- 8.9/.); goethil-hematil (TB: 10,1%); cac 70
Mjt dp mang ludi cdng trinh Uiam dd dugc ap dyng theo nhdm md tham dd 1;
thi cdng bing cic cdng trinh gidng, bd Iri tiieo mang ludi hinh cho nhat va da linh dugc ti* lugng cip 121 va 122. So cdng trinh gidng gap quang dua vao linh loan la 255. Trong bai viet cua minh, chiing tdi chi minh hga kit qua nghien cuu vd AbOj v4 Si02
•I. Phuong phap luan
Phuong phap chinh duoc ap dung la dja thdng ke, tuy nhidn vdi muc dich la djnh lugng khdng gian cac Uidng sd nghien cuu (TSNC), chiing tdi chii ydu chi nghien ciru khai Uiac cac ham ciu ttiic (variogram) ttong dia Uidng kd. Dd djnh hudng tdt cho nghien cuu cac variognim, dau tien ngoai vide nim bit tdt cfiu tiiic dja chal md ndi chung, Uian khoang ndi rieng, cdn phai djnh lugng Uidng ke cdc TSNC, bao gdm: kidm dinh cac gia duel Uidng ke (cac TSNC phan bd theo quy luat gi theo kdt qua xac cfinh cac bidu dd tin sd, phan bd xac suit, dp ISch, dp nhgn), sau do xac djnh cac dac tiimg Uidng ke Uieo luat phtn bd phii hgp: gia tti tiimg bmh (I), J ^ B p sai (2) va he sd bidn ddi (3). Neu H K . t t Uieo luat chuin, cac TSNC nay
dupe xac dinh bing cac edng Uidc sau:
Gid In trung binh: X
Z^'
n Neu TSNC phan bd theo luat chuin
- Phuang sai:
(1) '•<-f> = Z t ' ' . - £ ( - « ' ) l / ( J )
Cdng thirc tiigc nghiem:
« . „ = ^ ^ ^ ^ 3 ^ (2) - He sd biin doi:
C(/= V^!Miioo%;
E(X) Cdng thirc thgc nghiem:
I Variogram theo chiing ldi Id bteu dd biin thiin (TCDC).
K „ . , = J ^ . I 0 0 % (3) ttong do, Xi: gia tri cua TSNC lai cong tiinh thu i, nhu la mgt bien ngiu nhien
E(X), D(X): ky vgng toan, nhu la gia tri trung binh ciia TSNC
C(V), V(X): he sd bidn ddi cua TSNC
Tidp theo, xac djnh cac ham ciu tnic (variogram) it(h), gdm cac budc:
^ - Xdc djnh cdc variogram Ihuc nghiim bang cdng Uiuc (4). Dd nhan tiiuc linh bidn ddi ttong khdng gian Uian khoang.
lac gia da xac dinh cac y(h) tiieo 4 hudng khac nhau. Bi t?n dung tit ca cac thdng sd phan anh chil lugng quang tai tirng edng trinh Iham dd, Irong tinh loan theo hudng a nio dd, mdi gia tin Z(xii) kdt hgp voi tit ea Uidng tin ttong khoang [a ± da]
ma dao dgng xung quanh a. Mdi mgt lin ghep nhdm Uieo gdc a, da Uiuc hien ludn vipc ghep khoang each [r +e(r)] [1]. Da tien hanh xac diiih cac -rth) Uieo 4 hudng:
bac-nam, ddng bic - tay nam, ddng-tay va tay bic - ddng nam. Mdi mgt hudng dao dpng 22,5°. Nhu vay, tit ca 255 cdng tiinh gap quang ddu dugc Uiam gia Unh loan va sd lugng cap didm nghien cihi tang len rit nhidu lin (3.984 cSp didm Uieo hudng B-N; 4.431 eSp didm Uieo hudng TB-DN). Do do, dg tm cay ciia vi?c xac dinh cac y(h) ciing vi Uie tang len. De cd cai nhin tdng quan, cac lac gia da xac djnh eac -rth) cho ca cac TSNC da chuyen sang logaiit. Chiing tdi da danh gia miic dp dang tin cay eiia vide xac djnh va cac ham ciu ttiic Uiuc nghi'dm va sau khi da quy nap vd md hinh.
Cdng tiiirc ttiuc nghipm:
i
r(h)=^l[z,.-z,J^
(4)trong do, Z(x, va Z^x*\^): 2 gia Ui dua vao tinh a 2 diem tham do each nhau mpt doan h, va N{h): so cap diem tinh toan.
- Md hinh hda cac 7(h), tue la dua cac
•y(h) thuc nghiem ve duong cong Iy thuyet.
- Phdn tich vd khai ihdc cdu true dira vao cac dudng cong thuc nghiem v i dac biet la cac y(h) da ducrc mo hinh hda. Day I^ cfing viec rdt quan Uong di nhan thuc ket qua nghien ciiu. Qua do, ngudi nghien cmi ngoai vi?c dinh lupng duoc muc do bien doi con nam bat diroc dac tfnh, ciu triic su bien doi vi dinh lugng dugc tinh dang huong hay di huong (ca tung icigu di hudng) cua TSNC.
2. KSt qua nghien ctfu
Tat ca cac tinh toan d6u dugc cac tac gia thuc hien tren phSn mgm may linh chujcn dung cho d^a tiidng ke. K€t qua nghieii cuu, chting toi tha hi§n cr cac hinh vg tu s6 I d ^ so 4.
Bang ket qui dinh lugng .thdng ke (Hinh 1 va 2), hoan toan co thg quy nap cac TSNC vd phan b6 chuSn. Thong s6 AI2O3 bien doi thude loai rit d6ng diu;
Si02 thu6c loai biSn dfii dfing deu, tuy nhien tinh Ii8n tue ciia thfing so SiOi cd phan nao cao hoii.
Ket qua nghien cuu ciu tnic dugc th^
hien o cac Hinh 3 v i 4. Ca 2 thfing sfi d6u CO thS quy n^p vB mfi hinh ciu, cac dac tnmg dugc thfi hien 6 Bang I.
- - -
~- , ,
-,:
j ;
"^
LU J
3
i
.,
n
-I: h J '
Hinh 1. Biiu dd ldn sd vdphdn bSxdc xudt IhdngsSAhOi a va b chua doi ra logarit, c vddlheo logaril
H^Hi&ilfiiiri in. 1 ^ 1 1 , i
• 1 . 1
' ' J^
^'' ' - 11
I nitet - ' f.'^ J * '
sfJUs ^"2 PsoT ~ 2 a
| E U - Ills c l " " . , ? , "
Hinh I. Bieu do tan s6 vd phdn bd xdc xudt thdng sd AI2O3 avab chua ddi ra logarit, cvdd theo logaril.
! • i •
. / Y(ll)=2-4HC(250)
/
" * - " ^ — • — • -
"" ""^ '^'
p . I'S I 1
! .
r(li)-2.0HC(170)
1 .^ —'—•
.„.
tor*;
. M L U K:l-=
£ •
nL!"
"S 5«
is
1 • i
*
r(li)-I.9HC(20ll)
/•• • •• • •
— " 7 . . , , ^ " ""
• s : : 5 =
1 ;
r0l)-2.15HC(2S0) •LC-i
Hinh 3. Variogram IhdngsdAliOi theo 4 Huang
i
r'
(• .
—
. / •••..•
/ ' y(h)-l.lHC(270 •
1 • "
"...r
'" - E i - " =TSNC
AljO,
Hinh 4. Variogram thdng sd SiO, theo 4 hudng Bang t Tdm luyc kit qua djnh lugng khdng gian cic y(h)
Hudng tinh bac-nam
DB-TN ddng-tly TB-DN bic-nam DB-TN dong-tay TB-DN
Tiin cua y(h) (don vj)
2,40 2.00 1,90
A'J_
1,15 1,20 1,10 1,20
Kich thude anh hudng cua y(h)(m)
250 170 200 250 200 150 270 180
Nhan x^I C6 linh di hudng khu virc;
hudng bien doi m^nh nhil la DB-TN; chi s6 dj hudng la 1,7
Cd tinh dj hudng khu virc;
hudng bien doi manh nhit la DB-TN; chi sd dj hudng la 1,8
cac TSNC tiid hicn tinh dj hudng khu vuc nen ttong ndi bd than khoang khdng cd tinh ddn^ nhit cao, cin nghidn cuu chi tidt de CO die khoanh <)Bnh ra cac khoanh rieng va do vay mjt dp m^ing ludi cdng ttmh Uiam do CO Uie khac nhau (my khdng nhidu) cho cac khoanh rieng dd. Ngoai ta cdn cd tiid
•lmh hudng ve hmh dang va mat dd mang luoi diam dd eho tiian quang nghien cim nhu sau: mang ludi phu hgp cho tiian quang la l»nh cha nhat hoJc hlnh thoi khdng hoan ehmh (VI khdng can qua cdng nhic vd hmh dang mang ludi); ttong mdl sd tiirdng hop viec xe dich vi hi cac cdng ttinh tham ddcd
Unh den kk qua phan ti'ch ciu hue khdng gian lai phii hpp voi cau ttiic khdng gian thin khoang. Vdi sir ttg giup eda cdng ngh?
tiidng tin, chiing tii van cd Uie tao lap dugc cac he Uidng mat cit dja chit than khoang nhu yi mudn. Mat dg mang ludi tiiara dd dugc djnh hudng la, ddi vdi cip ttii lugng 121: (75-85) " (125-135) m; cip 122: (150- 170) X (250-270) m. Cjnh ngan ciia mang ludi ttieo hudng TB-DN.
III. TRAO B 6 |
1. Kdt qua nghidn ciru dua ra Irong bai bao chi la mpt vi du nho. chua day du cac tiidng sd cin duet, ttiy nhien phin nao da Uij ;
hen dugc Unh dac Uiu ridng cho UBU quang chpn nghis,, ^^^ ^ j ^ ^^^ dm loan dien cac ttidng so ciia nhidu ttian quang dac tiung cho md chic chin se cd kit qua'sat ttiuc hon.
Va day la CO sd chu dao cho vipc phan cip inr lugng va phuong phap kiigmg phu hgp tiong tinh trir lugng.
2. Dja thdng ke la phuong phap mdi, hien dai. Ddi vdi cdng tac danh gia chit lugng, sd lugng quang; phuang phap dugc xem la chu dao va bit budc d cac nude phat ttidn. Tuy nhien cdng lighe nay ip dung d Viet Nam chua nhidu. Qua nghien cuu a mgt sd md (dac biet d cac md cd ciu tioic dia chit tiian khoang phirc tap nhu cac md vang, ddng,... va ca trong nghien cuu mdi trudng, npi suy khi nghien ciru hp thong tin dja ly va cac dii
^yjjvidn Uiam), chiing tdi da Uiu nhan Brgc kit qua rit kha quan.
nenie
QUOC
VAN LIEU
1. Goovaerts P., 1997. Geostatistic for resourse evaluation Stanford University.
2. Trmmg Xuan Luan, 1991.
Variogram et krigeage sur un gisement d'or du Colorado. Rapport a I'ENSMP. Paris.
3. T n n m g Xuan Luan, 1995. Ap dung cac phuong phap dja Uidng kd nghien cihi mpt sd md than. Bdo cdg HNKH Big chat VN ky niem 50 nam thdnh lap ngdnh Dia chdi VN. I - 423- 430 HdNgi
4. Tnrolig Xuan Luan, 1997. Vai ttd eua ham ciu tiiic ttong nghien ciiu danh gia cac md khoang. Tgp chi Bia chdt vd nguyen lieu khodng. 2/1997. Hd Ngi.
5. Tnroog Xuan LnSn, 2005. Dja Uidng ke va tin hpc img dung ttong dja chat. Bdi gidng sau dgi hgc BH Md - Bia chdt. Hd Ndi
SUMMARY
Quantitative study on parameters reflecting the ore quality: Case study on bauxite ore bodies in ttie lateriBc weathering crust
Truong Xudn Lugn. Buong Thi Tdm. Le Vdn Luang In tiie creation of basis for Uie rational exploration of deposits, die essential problem consists of approximate approach of variation of parameters reflecting the ore quality. Basing on ttaditional meUiods, we can understand only the level of variation but not Uie peculiarity and sti^cture of variation of Uiese parameters. By tiie use of variograms in geostatistics, Uic auUlors of ttiis article have been carrying out the quantitative spatial stiidy on parameters characterizing Uie ore quality and having the role of causing difficullies to Uie deposit exploration. They have been recognizing Uie variation character of stildied parameters in Uie space of each ore body and so eontiibuting in tiie modernization of tiie evaluation of deposits. -The auUiors have been using informations received ftom bauxite ore bodies lying m ttie typical lateritic weaUiering crust of a deposit in ttieir calculations. The use of study results on the AI2O] and SiOi has been allowing tiiem to estimate ttiat boUl of ttlese parameters have the near-standard distiibmion, among tiiem AliOj belongs to Uie type of very regular variation, while S1O2 - regular variation. However, tiley have differea vaiiaion charactenstics: SiO, changes more complicatedly tiian AI^Oj and has manifestation of regional anisottopy. These results create Uie basis of selecting Uie fonn and density of Uie exploration network conforming with ore bodies.
Ngtrdl bien ldp: Trdn Vdn Miin.
