m extraction error at plant (new)

7/23/2019 M Extraction Error at Plant (New)

1/231

The INCREMENT EXTRACTION ERROR

at the plant

The INCREMENT EXTRACTION ERROR

at the plant

Like the INCREMENT DELIMITATION ERROR, the INCREMENT

EXTRACTION ERRORIEE introduces the largest biasesencountered in sampling

The Rule of the Center of Gravity must be respected

All !ragments ha"ing their center o! gra"it# inside the model

e$tended increment belong to the model e$tracted increment

M u s t f a l l o n e i t h e r

s i d e

a t r a n d o m


2/232

Conditions of e!traction correctness

relative to the cutter characteristics

Conditions of e!traction correctness

relative to the cutter characteristics

Conditions li"ely to play an important role

% &traightness o! the cutteredges

' Thickness o! the cutteredges

( &hape o! the cutteredges

) Length o! the cutteropening

* Inclination o! the cutteropening

+ Cutter idth

- Cutter speed

. Depth, capacit# and general design o! the cutter

/ &tream turbulences and stream "elocit#


3/233

#trai$htness of the Cutter Ed$es

#trai$htness of the Cutter Ed$es

C o r r e c t

I n c o r r e c t

0e assume that both cutter edges are

straight and perpendicular to the cutter

tra1ector#

The main condition to !ul!ill is to ensure

that the trailing edge is per!ectl#superposable to the leading edge,

% 2# a translation for strai$ht path

cutters, or

' 2# a rotation for circular path

cutters


4/234

Thic"ness of the Cutter Ed$es

Thic"ness of the Cutter Ed$es

L e a d i n ge d g e

T r a i l i n ge d g e

I n n e r w a l l s

G a i n e df r a g m e n t

L o s tf r a g m e n t

C u t t e r d i r e c t i o n


5/235

#hape of the Cutter Ed$es

#hape of the Cutter Ed$es

I n n e r w a l l s

F r a g m e n t g a i n e d w i t h

d i f f i c u l t y

a s i l y l o s tf r a g m e n t

C u t t e r d i r e c t i o n

T r a i l i n ge d g e

L e a d i n ge d g e


6/23!

Ad%ustable cutter ed$es

They may ruin the correctness of thesamplin$ system&

Ad%ustable cutter ed$es

They may ruin the correctness of thesamplin$ system&

C u t t e rt r a " e c t o r y

#ccumulatedmaterial

The leading edge o! a rotating cutter ma# ala#s be dirt#, hile

the trailing edge sta#s clean

Also, ad1ustable plates are rarel# kept per!ectl# s#mmetrical

#d"usta$le%late


7/23&

'esi$n of the Cutter Ed$es'esi$n of the Cutter Ed$es

' a d ( e s i g n s

G o o d ( e s i g n

& ) o*

+

+ >

*


8/23,

(en$th of the Cutter Openin$(en$th of the Cutter Openin$

- t r e a mI n c r e m e n t

- t r e a m

I n c r e m e n t

L o s t f r a g m e n t

. e c o / e r e d f r a g m e n t

0 r o n g e t r a c t i o n

C o r r e c t e t r a c t i o n


9/23

The secondary stream must be

represented in the sample&

The secondary stream must be

represented in the sample&

- t r e a mI n c r e m e n t

12

1 M a i n s t r e a m2 - e c o n d a r y s t r e a m


10/231)

Inclination of the Cutter Openin$

Inclination of the Cutter Openin$

I n c r e m e n t

- t r e a m

- t r e a m


11/2311

Cutters should not be vertical&

Cutters should not be vertical&

I n c r e m e n t - t r e a m

- t r e a m


12/2312

The cutter should not overflo)&

The cutter should not overflo)&


- t r e a m

olume of material %resent inside the cutter

Time

Maimum acce%ta$le /olume in cutter

-tream cutting time (ischarge time


13/2313

Many cutters are poorly desi$ned&

Many cutters are poorly desi$ned&


- t r e a m

?


14/2314

The cutter must cross a *uiet stream&

The cutter must cross a *uiet stream&

e e d l e

t a n 6

0 o r 6 i n g% l a t f o r m

D i v e r g i n g

c h u t e

3or e$traction correctness to take place, the stream should not

tra"el !aster than + meters,second


15/2315

A cross-stream buc"et cutter should not

$et more than .,/ full&

A cross-stream buc"et cutter should not

$et more than .,/ full&

C o r r e c t I n c o r r e c t


16/231!

Recommended cutter desi$n for

samplin$ stic"y material

Recommended cutter desi$n for

samplin$ stic"y material

+

*

Y X


17/231&

Recommended cutter desi$n

Recommended cutter desi$n

0

4

5

6

7 ' 8

9 e r # h a r d s t e e l ,p e r ! e c t l # s # m m e t r i c a l

c u t t e r b l a d e s


18/231,

E!tremely narro) cutter openin$s cannot

)or" properly&

E!tremely narro) cutter openin$s cannot

)or" properly&

A mo"ing cutter opening cannot be smaller than . centimeter


19/231

Cutter )idth re*uirements for e!traction

correctness

Cutter )idth re*uirements for e!traction

correctness

The !olloing rules are based on e$perience and are notuni"ersal

#olids lar$er than 0&/ centimeter

dWW 3) =

W 0


20/232)

Cutter )idth re*uirements for very lar$e

flo) rates in floatation plants

Cutter )idth re*uirements for very lar$e

flo) rates in floatation plants

)

1 ) ) )

2 ) ) )

3 ) ) )

4 ) ) )

5 ) ) )

! ) ) )

& ) ) )

, ) ) )

) ) )

1 ) ) ) )

) 1 2 3 4 5 ! & , 1 )

. e c o m m e n d e d c u t t e r o % e n i n g 0 ) i nc e n t i m e t e r

- l u r r y s t r e a m f l o w r a t e

i n m 3 7 h o u r


21/2322

Cutter speed re*uirements for the

e!traction correctness of rotatin$samplers

Cutter speed re*uirements for the

e!traction correctness of rotatin$samplers

V 0


22/2323

E!traction correctness of riffle splittersE!traction correctness of riffle splitters

Do not !eed ri!!le splitters too !ast

C o r r e c t I n c o r r e c t


23/23

Riffle splitters are easily misused&Riffle splitters are easily misused&

m extraction error at plant (new)

Documents