MINE 302 - Assignment 2

7/23/2019 MINE 302 - Assignment 2

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The University of British Columbia

Department of Mining and Mineral Process Engineering

'MMPE 302

Mining Methods and Equipment

Assignment #2

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Method Selection

You are given the enclosed plans, sections, longitudinals, geology, fabric infonnation, strength,

stressamong other infonnation for the Main Zone of the Myra Falls Operation. The ore is massive

sulphide with rock mass ratings and distributions as indicated in the enclosed reports. The footwall

is andesiteand the hangingwall is rhyolite. In all cases a variation in degree of alteration occurs to

reflect the rock mass ratings shown in Figure A. Generally the footwall and hangingwall for stope

areas west of 3700E on Figure A are slightly altered and east of 3700E can be considered to be

strongly altered and RMR values as per Table 4 for the andesite and rhyolite rock types. Use the

orientation of the ointing as shown n Figure A. The ore is 2% copper and the host rock surrounding

the ore is 0% copper. Surface is at 3367m.

Objective: 1) Determine what mining method/methods o be used or the Main Zone shown in Fi~

A. You must ustify all assumptions and conclusions made employing I\IfMPE 302 course notes,.¥

reference e. Nicholas Method/requirements/etc.Show all sections,plans and proposed longitu~s

for the stoping blocks that you will design for the Main Zone. Show the development and access

required and size of openings for a 2000 tonne per day orebody (employ diagrams/sketches).Marks

15/20

2) What equipment is required for this area n tenns of drilling, blasting and haulage given

the above constraints and a production from this area of 2000 tonne per day. Marks 5/20

The report should include the following;

I) Cover Page/Scope of Study

2) Introduction

3) Methodology/Results

4) Observations

5) Conclusions and Recommendations

Some assumptions may have to be made, however, employ your course notes to arrive at solution

to the above problem. The overall report should be limited to 20 pages ncluding diagrams.

NOV 21

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H-W MAIN ZONE. OREBODY ISOPACH FIGURE

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H-WMAIN ZONE - OREBODYHANGINGWALL FlGURE

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HoW MAIN ZONE. OREBODY FOOTWALL CON-fOURS FIGIJRE

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SUBJECT: TYPICAL V /\LUES FOR ROCKMASS CLASSIFICATION -HW ~

UPDATED 25 OCTOBER 1996

file: WR.96_13.dc.:

The foUo\1fingable9give typical values or rockmass lassificationparameters t the HW Mine. These

tables areprovided o allow "fust pass" stability analysis o be carriedout without. actual mapping,and

also to provide or comparisonof mappedvalues.Values outside he given angesare possible)

however, f they do occur they should be recheckedor accuracy.

TABLE 1: GEOLOGIC STRUCnJRE - HW MAIN ZONE (dip/dipdirection)

ROCK1YPE ALTERA'nON 1 2 3 4 5 6 7 g

flat fault schi$tosity a-c oint joint 1 joint 2 joint 3 splay ault mull

ANDESrrE SLIGI-rr 50/050

ANDESrrE STRONG 501050 75/045 75/330 75/090 70/150 65/030 80/020 82/085

RHYOIn"E SUGHT

RHYOr..rn: STRONG 50/050 75/045 75/330 75/090 70/150 65/030 80/020 Sl/OS5

CfrERTYRHY SUGlrr

CHERT SUGHr

QFI' SUGHT

FAUt T ZONES COMPLETE 501050 75/045 75/330 7S/090 70/150 65/030 80/020 82/085

ORE FRF.5H 50/330 75/250 70/150 SO/SO 20/110

NO1ES: 1) Orientations or geologic structurc are +/- 100 or dip. +/- 1.5° or dip ~on.

2) Thc table ists geologic stru~ that may be prcscnL Not all geologicstructW"c:src present in a.lllocalions,

ie. in are hcre is typically only 2 or 3 oint $CIs,n StrOngly 1te~ roc:k lt~ is typically 3 or 4 oint sets.

TABLE 2: GEOLOGICSTRUCTURE GOPHERZONE (dip/dip direction)

ROCK TYPE ALTERATION 1 2 3 4 5 6 7 g

major ~jor foliation minot minor fiat fault foliation shan

ANDESn'E SUGHT 89/097 63/014 78/326 S4/198 26/079 30/350 80/020 65/360

ANDESfl£ STRONG 89/097 63/014 78/326 54/198 26ro79 30/350 &0/020 65/360

HYOUrE SUOHf 891097 63/014 78/326 54/198 26/079 30/350 &0/020 65/360

.

RHYOLn"E S1"RONG 89/097 63/014 7&1326 .14/198 26/079 30/350 80/020 65/360

CI-IERlY RHY. SUGI-rr

FAULT ZONES COMPLETE 89/097 63/014 78/326 54/198 26/079 30/350 80/020 65/360

ORE fRESH 89/097 63/014 78/326 54/198 26/079

NOTES: 1) Oricntauons or geologic stru~ arc +/- 100 or dip, +/- 150 or dip dirt(:tjon.

2) The ublc lists geologic stru~ that may be p~scnt. Not al gcologic: w~cs arc pRsent in alllOC1ltions,

ie. in arc lbe~ is typically only 2 or 3 oint sets) n strongly altered rock there s typically 3 or 4 oint sets.

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wr:snll'" USOURC J. HW M~ Z'/IOI'J', pIC-Z MICHAEL CULLEN ~1.En&..En,-

n.PIC,1.l.V.\LUU PORROCK..\tJUSLA.1stnC,\T10~ ~TNat:I~~CHN]CALINO~"U.B.

TABLE 3: GENERAL CLASSIFICATION VALVES

ROCK TYPE ALTERAll0N U.C.S. RQD PERCENT

(MPa) RECOVERY

ANDESrrE SLIGl{T 125-250 70 - 100 100

ANDESm STRONG so - 100 40.60 9& 100

RHYOurE SUGH 125 200 70 - 100 100

RHYOLm STRONG so - 100 40.60 98 - 100

CHERTY 'BlrY. SUGHT 100 ~200 10 ~ 100 100

ARGILUTE SUGHT 30

-

1 o 40

-

go 100

QFP SUGKr 100-175 60 -100 100

FAULT ONES COWLETE 1 25 0 - 40 80 98

ORE FRESH 100 300 50 - 100 100

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TABLE 4: RMR CLASSIFICATION VALVES (1976)

ROCKTYPE AL rEM 110N S"IUNGTH RQD JOINT 1000 GROUND 10n-rr

SPACING CONDmON WATER ORlENTA1ION

ANDESrrE SUGffi 12 13-20 12-25 12-20 10 -10

ANDESITE STRONG 4 - 7 5 - 10 10 15 0 -12 10 -10

RHYOLn'E SLIGHT 12 13-20 12-25 12-20 10 -10

RHYOUTE STRONG 5 - 7 8 -12 10 15 0 -12 10 -10

CHERTY RH¥. SUGHr 7 - 10 5 - 10 10 15 12 20 10 -10

ARGD..Ln'E SUGHT 12 13 8-12 15-20 10 .15

QFP SUGlfi" 7.10 12 20 10

- 15 10

- 0 10 -10

FAULTZONES COMPLETE 0.2 3-8 S 0 7-10 4]0

ORE FRESH 7-15 13-20 15-30 6-25 10 -]0

TABLE 5: Q CLASSIFICATIONVALUES

ROCKTYPE AL1DAllON RQD Is IT J.

ANDESnE SUGHT 70 -100 3 - 6 2 - 4 1-2

ANDESnE STRONG 40 - 60 6 - J2 ].5 - Z 2 - 4

RRYOLn'E SUGHT 70.100 3-6 2-4 1-2

RHYOun: STRONG 40 - 60 6 - lJ 1.5 2 2 - 4

CI-JERTY HY. SLIGHT 80 -100 4 - 9 1.5 4 0.75 2

ARGIWTE SLIGHT so - 60 4 - 9 1.5 3 1.2

QFP SUGHr 60 - 80 4 - 9 1.5 2.5 1 - 2

FAULTZONES COMPLETE 0-40 9-15 0.5-1.5 4-lJ

ORE fRESH 50-100 2.9 1.S-] 0.75-2

IN SITU STRESS

,

Vcrrical ~s is equal to overburden \\'Cight (0.028 Mpa p~ m depth)

Ma QrnW11 orizontal stress (0'\) is equal [0 2 times the vertical suess with oricntation 1 14OFJ04°.

Minimum borizonto'llstrcss (a1) is cqual to 1.1 times thc ~rtical ~S with oric:rtarlon 02S~ ISo

Th~e values arc consistcnt \vith ~S estimates ba. cd on anal~.sisof earthquakes, regional tectonic 3.~~. and

prcv1ous mess measurcmeDCSarri~ out in f-IW Min~ foot\\-a1] rOCKS. Tho va1u~ arc not consistent \vith

prcv1ous ~s measu~ents taken in the ore zone. VisuaJ observatiOD-' f strcss related failures suggest hat the

oricntation and magnitude of stre.sscscan vary signifiC4lntly throughout tho mino, pouticularly in close pro.'Cimity o

faultin&.

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.

4.1 GEOW<;YOF THE HeW MINE.f

The ore depositsof Westrnin Resources cd.'s Myra Falls Operationsoccuras ndividual oreb<x1ies

grouped nlO severaJmajor zones. This casestudy s basedon he Main Zone of he H-W orebody. The Myra

Falls ore deposilS re polymelaJlic massive ulphidedeposirsassociatedwith felsic volcanic ocks. The ore

formed as sedimentary enseson the sea loor, precipitated rom melaJbearinghot springscontemporaneous

with felsic volcanic rocks. Hot spring activity producedwidespreadhydrothermalalterationof waJlrocks.

particularly below he ore lenses. Hydrothermalalteration s represented y sericitization.silicification. and

pryritization. A generalizedcross-sectionof the H- W Mine with the larger ore enses s shown in Figure 37.

The ore minerals are: pyrite. sphalerite. halcopyrite,galena and barite.all of which vary widely in

heir proportions. Occurrencesof rhyolite. sulphidesand altered rocks are distributedverticalIy and lateraJly

".,

within a stratigraphic zone approximately 400 10 500 metres thick. The mine sequence ies within the Myra

formation of he PalaeozoicSicker Group. The mine sequences comprised of massive olcanic and coarse o

fine volcaniclastic ocks. which include basalt.andesite. acite and rhyolite. as well as subordinatesedimentary

rocks which include chen. carbonaceous rgillite. sulphidesand barite. The mine sequences intemaJly bedded

and is predominantlymafic and volcaniclastic. Li hologic unirs are aterally discontinuouswith a distinct

.

northwest rend which parallel the trend of the ndividual orezones.

5 Thc lcoqical dcscripcioo ~ in this scctioo s ~ced ~milW\lIy (rom Walka. 1983.

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WESTMIN .

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Fi~ 36: Location plan ofWestmin Resources Id.'s Myra Falls operations.

The H-W orebody and associatedensesoccur at the baseof. and within. the H-W rhyolite unit which

lies at the bottom of the mine sequence.The mine sequence as been olded and metamorphosedn the ower

greenschistacies. Deformational abrics are variably developedwith widespread ccurrenceof schistose nd

lineated ocks. Schistosity s most ntense n sericitic rhyolites and altered ocks. Schistosity strikes northwest

anddips steeplynortheast. Lineations. as well as fold hinges, rrend northwestwith flat to very shallow plunge.

Post~tamorphic faultsoffset heorezones ndzones f brokenground common longmajor aultsand

ore con~cts. Most notable s the east-west biking flat fault againstwhich the Main Zone of the H-W orebody

tenninates o the north. A seriesof east-west 'ending aults are present n the southernponion of the orebody.



_ --

. .

TheH-W orebody has a thickne.'sof 60 metresat the core and tapersat the margins. The majority of

the arebody s belW~n 10 metresand 40 metres hick. The orebodyexhibits strong ateralzoning ranging from

a very massive,pyrite core with high copper-zinc atios. to zinc and barite rich marginswith low copper-zinc

ratios.

HW Ww,8 ~

theodfrane ~ Nor

Price

(11.045 II) Portal

13 Level Myra

13 L.~

(3289.4) R.turn

Fresh Air

Air Raises

Raisn

Escape

Manwoy

18 Le.el

(JO~.5

20 L.'"

(2962.8)

~1 Level

(2918.0)

23 L.'"

(2825.J)

24 L.~

(2779.J)

North Lens

2~ L.""

(2719.6) 0 100 metres

25 L.""

(258J.J)

27 L.""

(25~21) 0 ~OO 'eel

. ,

LoadIng

Pocket

Figure 37:, A simplified I:ross-section of the H. W Mine showing the location of the shaft, lateral development

and the major orebodies.

-I 57

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4.2 MINING PRACTICE AT THE

H.W MINE

Variations of ~veral different mining methods ave been used at the H-W Mine. Listed below ~ the

methods that have accounted for the bulk of the production from the H.W Mine:

. blastholeopen stoping

. cut-and-fill post-pillar

. cut-and-filllongitudinaJ

.

room-and-pillar

The more steeply dipping. southern flank of the Main Zone has been primarily mined with

longitudinal cut-aDd-fill stapes. augmented by longitudinal blasthole staping. The core of the orebody has been

mined primarily with cut-and-fill post pillar stopesand the north flank has been mined using transverse

blasthole open stopes. The smaller. gently dipping tabular lenses to the north of the Main Zone have been

mined using room-and-pillar methods. Figure 38 is a simplified cross-section through the orebody looking

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0 Z4~)4 DRIFT

Z4-))1 DRIFT

LONGHOLE

34.90

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I.COKING WESTI

.

Figure )8: Sl:hemiltic of mining method and the respective location

within heorebody sed n the H-W

Mine.

58

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.

.

we~1showing the local Ion within Ihc oreb<Jdy f ea<:hmining mcthc)(j u'icd Hydraulil:ally placcd cemented

backfill is used in all ~IOp<:S.Figure 39. Figure 4{). Jnd Figurc 41 sl:hcmalically illustrate op<:nsloping and

room-and-pillar mining methods.

In 1989. he mining praclices al the H-W Mine were abruplly changed rom 80% cul-and-fill post-

pillar and 20% blasthole methods1090% blastholeand 10% cul-and-fill post-pillar methods. This resulted n

lower mining costs hrough the reduclion of manpowerand equipment requirements.Blastholestopesare

drilled off using either 57 mrn or 89 mm blastholes p 1020 me[TeSn length. Sloping blocks are variable in

size and shape.with the largest blastholestopecreated o-date being 25.600m3. Smallerblocks of

approximately7.500 m3 are more frequentlymined. The mining methodsemployedhave necessitatedhe

developmentof a number of barrier pillars in the orebody. These barrier pillars containnumerousopenings

which include: drifts. drawpoints. ore passes ndraises.

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Figure 39: Sl:hcmalic ayout for sublevelopen i((lping wilh ring-drilled bl;L'i1 olc~ (afler Hamrin. 1982).

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Figu~ 41: Elcmcnts of a sup~)r1cdmcth(>tJIf nllnlnl,: (~flcr HJmnn. I ).I(~)

60

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4J WESTMINN-SITU DATABASE

A datacollection program wu underu.ken n order to determine he distribution or the in.situ rock

masspropcniesat Westmin ResourcesId.'s H-W Mine. This sectionpresentshe results or the data collection

program.

4J.l Intact StrengthAnalysis

In order o assess he strengthor a rock mass.knowledge or the n~t rock strength s required.

Sampleswerecollected from five locations hroughout he H-W Mine. representingmassivesulphide ore,

hangingwaJl olcanics. ootWall volcanics,altered ootWall volcanics,and elsic dyke in order to assesshe

inrxt strengthproperties. Sampleswere obtainedat depthsbetWeen 40 metresand S40merres below surface.

Testing wu carried out [0 ISRM standards t me Mining Research aborarories Gorski & Conlon, MRL

Report92-027(InL», Ottawa to detennine he following intact rock properties:

.

unconfined com~ssive strength

.

tensile rrength

. elastic modulus

...,..

. poisson'satio

The esulrs f this resting rogram representedn Table8.

4.3.2 Fabric Analysis

Geotechnicalmapping was undertakenat all accessible ocationswirhin the barrier pillars throughout

the H-W Mine - Main Zone and imited mappingwas undertaken n me footWallvolcanics. The geotechnical

datacollected ncluded structural featuresand rock massclassification. The parameters ollected for each

srruc~ mappedwere:

.

orienration

.

infilling

. roughness

.

length

.

continuity

. openness

.

hardness

.

waterconditions

. planarity

,

"

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.

Table 8: We~rmin intact ockpropertiesor the H-W Main Zone.

A verage Standard Count

Deviation

(MPa) (MPa)

172 4 3

70 17 4

91 31 4

ar p kc 147 12 3

Altc~ FootWallAndesite 29 13 6

Tensile Average Standard Count

Strength Deviation

(MPa) (MPa)

12 12 7

4 nla 2

13 13 8

16 16 13

13 6 6

Elastic Average Standard Count

Modulus Deviation

(GPa) (GPa)

166 2 3

63 3 4

45 10 5

71 5 3

24 10 6

Average Standard Count

Deviation

0.15 0.06 3

0.12 nla 1

0.26 nla 2

0.25 0.04 3

0.32 0.3 3

Three joint sets were identified. one major. one intermediate. and one mjnor. The major joint set

corresponds to the orientation of the foliation of the volcanics and the major faults in the mine area. The

orientations of the joints sets are presented graphically on Figure 42 and are tabulated Table 9.

62



.

. .

Join t Set 8

159/75 W

Join t Set A

251/57 N

Join t Set C

058/68

S

N:,~:l

East

Figure 42: Isometric vi~w showing the major joint sets identified within the H-W Main Zone.

..,..

4.3.3 Rock Mass Clllssijication

Rock massclassification ~rding to the CSIR-RMR medlod. (Bieniawski, 1913),was performed

dlroughout the barrier study areaat approximately en metre ntervals along drifts within the barrier pillars.

Rock massquality within the barrier pillars varied from a fair-good (RMR ~) to good-very good quality rock

mass RMR 80%). It must be noted hat. due to the extent of mining. the RMR values ecorded epresent

,;,

induced rock mass atings within the pillars and not the pre-mining rock massquality. Areas of the mine

subject o lower stressconditions,as determinedby modelling, were observed o havehigher rock mass

classification ratings.

4.3.4 Geometry

The H- W Mine orebodiesconsistof the Main Zone. he North Zone and a number of smaller zones.

The casestudy domain was confined to the Main Zone orebody.which hasapproximatedimensionsof 850

me~s in strike length and 220 me~s in width. The Majn Zone orebody varies n dip from 200 o 500 to the

north and plungesat approximately 100 o the west. Mineable thicknessvaries rom approximately 10 n1elres

in the south to 40 me~s in the north-west

The study requireda detailed understanding f the mine geometry n thttt dimensions. This was

accomplishedby cn.nsforming Wo-dimensionalmine sectionsand plans nto a three-dimensionalmodel within

AutoCAD. This hree-dimensionalomputermodel ormed he rameworkor thenumericamodelling

hase

of .heproject Figure 43 and Figure 44 are somebic views of .heWee-dimensional eometric model showing

sloping blocks and barrier pillars respectively.

63

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Table 9: Summary of joint fearure~ r the Weslmin H.W Main Zone.

SetA . 17'2 bs. Average SId. Dcv.

Strike

deB.)

251 18

Dip (deg.) S7 N 17

Length m) 7.1 ).)

End Visible 0

P1anariry Planar .

Wavy

Roughness 9

Openness

tight

SetB

.

172obs. Average Sid. Dev.

Strlke(deg.) 159 19

Dip (deg.) 7S W 16

~gth (m) 3.3 2.1

End Visible 1

P1anarlry Planar

Rou hness 12

OpeMess tight

Set C - 9 obs. Average Sid. Dev.

Strike (deg.) 058 20

Dip (deg.) 68 S 17

~gth (m) 4.7 3.0

End Visible 1

P1anariry Planar

Roughness 7

Openness tight

43.S In-Situ StressDetermination

Triaxial overcoring s~ss measuremenlS0determine n-siru stress onditionswere performed at two

locations n he H-W Mine by the Mining Research aboralories.Elliot Lake Onto Arjang & Stevens.MRL

Report91. 144(TR». The in-situ test was performedalthe shaft stationon 23 Level. al a depth of 600 metres.

10detennine he cumnt state of in-siru stress n the vicinity of the H-W Mine. The resullSof he in-situ triaxial

test arepresented n Table 10. The resullSof the biaxial in-situ stressmeasurementrogram. which was

performedpreviously allhe H-W Mine. are presentedn Table II"

64



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N

Figure 43:

Isometric iew showinghe ocation f stopeswith theH-W Main

Zone.

3+M;

:

N j

I

~

,37

600

:t'tl 355

"""" / .

Figure 44:

Isomeaic

view showing the

local

on of Ihe b;uricr pill~ wilhin

the H.W Main Zone.

6.5

~"

"



-.

Table 10: In.siN lriaxial suess measu~~nl ~sulu al the H-W Mine.

Principal Muiliplier MaaniNde

S~ss MPa

01 1.90. 36 USE TH'S

02 1.10. 20 N025.E/18.

0, 0. 19 Vertical

Table I I: In-sibJ biaxial SIreSS easure~nt resultsat the HoW Mine.

Principal Multiplier MagniNde Orienlation

SIreSS MPa Direction Ptun e

0, 2.250. 34.2 N 021.E 127.

OJ 1.810. 27.5 N2<xJ8E/OI.

0) 0.

15.2 NIOS.E/63.

Figure 45 (a) is a stereonetplot of be Iriaxial in-sibJsb'eSS ure~nts and Figure 45 (b) is a plot of

the historical measme~nts (biaxial d~). Figure 45 shows hat the orientationsof dte principal

s~ determined rom dte two programscompare avorably. The major diffe~nce between hese wo .,..

programs s dte magnitudeof d1ehorizontal components f the n-sibJ SIreSS. he ratio of horizontal to vertical

stress or dte biaxial program were ower dtan dIoseof the biaxial program. This was most pronounced or

ON-S. hichwas2.25Oy or d1ebiaxial program and 1.1 O'vor the biaxial program. The ~ults of the biaxial

progr3JnWeIeused rx nwnericaJmodeIJingpwposes.however.dte impact of the polentiaJlyhigher stresses s

predicted by the biaxial program was nvestigatedwidt a pararnebicmodeIJing ession nd s discussedn

Section 4.4.1.2.1.

N

\

.

.

£

.

£

s S

In-$;I..SIr... Plo T"o..oj cor. 2J L 5101- In-Sil..Sir... - B,o...1leo~'.m."I.

Figure 45: Polarslereanelplou of he multi of tho biuW and the biaxiaJ n-siN Slre.s.sclSu~mcnt

proaramswithin he HoW MaiD Zone.

Documents

MINE 302 - Assignment 2