7/28/2019 OpsIll_AGRM051011

1/4

pull-outguideby Therese Dunphy, Editor-in-Chief illustrate

DontSetleforPondProb

lems

Locate the settling pond in a low area, with naturaldrainage. Keep it away rom streams and wetlands.

Maintain a capacity o at least 110 percent o the

water volume needed by the wash plant.

Clean the settling ponds regularly.

Keep settling ponds away rom material likely toblow into the settling ponds, such as stockpiles

7/28/2019 OpsIll_AGRM051011

2/4

A Primer in Polymers

opera

Planning ahead pays big divi-

dends or producers who de-

ermine how o handle heir

recycled wash waer and

nes a he ouse, says Bob Gralon,

presiden and owner o Clearwaer

Indusries. Te bigges hing aggre-gae producers need o know is he

opporuniy coss, he says. A lo o

people don pu a pen o ha.

And while he real esae value o

land used o accommodae setling

ponds is a signican upron cos,

he equipmen, labor, and maine-

nance coss involved in setling pond

mainenance are no always acored

ino an operaors nancial analysis

o heir operaion, he says.

Unorunaely, producers oen ex-

plore heir setling pond opions and

alernaives as land or waer issues

are becoming a problem, no beore.

John Gralon, he second generaion

in he aher-son eam and general

manager a Clearwaer Indusries,

jokingly compares his responsibili-

ies o hose o a procologis he

handles he ail end o he operaion

ha no one wans o deal wih unil

i becomes a problem.o deermine good soluions, he

says ha rs and oremos, we have

o lisen. Ten, like a physician, he

can deermine wha sympoms need

o be abaed and oer he correc

prescripion. For example, when he

ooprin is a major concern, and an

operaor needs o eliminae all bu

one setling pond, a polymer sysem

migh be he bes opion. I hey wan

no setling ponds a all, and a moreconained, conrolled process, a clari-

er may be needed. A he oher end

o he specrum, an emulsion polymer

may mee he needs o a simple opera-

ion. Tere is no one-size-s-all an-

swer o dealing wih he issue.

While he righ soluion depends

on myriad acors, a litle oresighled some producers hey have

worked wih o develop ideas ha

could bene oher sies. John Gral-

on poins o an operaion ha se

up is clarier on an elevaed poin

o he plan. By placing i on higher

ground, graviy aids he ow o solids

being pumped rom he clarier and

can exend he lie o he pumps.

When locaing he clarier, anoh-

er consideraion is where o pump

he maerial. Bob Gralon noes, An-oher very good pracice is or he

producer o hink abou pumping his

solids o a locaion where hell never

need o deal wih i again. A com-

mon applicaion is o pump hem o

a porion o he sie being reclaimed

and use he maerial or ll.

I a polymer make-down uni is par

o he sysem, boh aher and son rec-

ommend he use o an enclosure. Is

a good pracice o pu everyhing inan overseas shipping conainer, noes

Bob Gralon. He says ha by doing so,

he small waer lines used or he poly-

mer make-down sysem are less likely

o reeze and can be used during he

hip monhs a he beginning and end

o he producion season.

By planning ahead, producers have

opions o recover saleable maerial,

reduce waer and land use, and exend

heir producion season all leadingo longer, more proable sies.

AggregAtes MAnAger

When designing a settling pond, consider evaporation rates anease o maintenance. Deeper water creates less surace water ensure slower evaporation, while a narrow width makes or eamaintenance via excavator or dredge.

When space is an issue, above-ground settling tanks oer an aternative with a smaller ootprint. Flocculants can be added to water to allow immediate recovery o usable water.

1

4

Basic design

Settling tanks

7/28/2019 OpsIll_AGRM051011

3/4

ionsillustrated ourexpertson Setle for Unwaned Fines

May 2010

John Gralton is generamanager or Milwau-kee-based ClearwaterIndustries. He has beenwith the business orseven years and regu-larly advises producersacross North Americaon these issues. He can

be reached at john@clearwaterind.com.

Bob Gralton is presidenand owner o Clear-water Industries inMilwaukee. In 1988, hejoined a company thatmanuactures clariersand concrete reclaim-ers. He ounded hisown company in 1996.Gralton can be reachedat 414-365-1200.

pically, the distance water travels within the sett ling pondould be three to ve times the width o the pond. I acreagea concern, bafes can be used within the settling pond toate the distance.

A series o settling ponds, moving rom coarser to ner solids,allows or additional amounts o material settling. In addition,when one pond is being c leaned, the other pond or ponds cancontinue to be used.

ones spin dirty water to separate particles rom the liquid.ger particles, which may be marketable, are removed. Thealler particles are typically ed into a settling pond whereculants are oten used to promote settling.

Clariers provide an alternative to settling ponds. Inside the clarier,nes settle toward the center o the tank and are raked to a dischargepoint. Clean water is sent back to the wash plant or re-use.

3

6

Consider water ow Expand as needed

Cyclones Clarifers

7/28/2019 OpsIll_AGRM051011

4/4

perationsillustrate

AggregAtes MAnAger

Voices of Experience

T

he righ choice or dealing wih ne maerials ypi-

cally sen ino setling ponds depends on a producersprioriies, says John Gralon, general manager o

Milwaukee-based Clearwaer Indusries.

He says ha hell ypically visi a sie, alk o operaors, and

develop a grasp o heir prioriies, paricularly hose concern-

ing maerial recovery, land use and value, and waer use and

availabiliy. By perorming a paricle size disribuion es,

he can hen deermine i maerials ha may be saleable are

being sen o setling ponds. A common example, he noes

is wih limesone operaions where ulra-ne maerial can be

capured and used as aglime or arm elds.

In many operaions, larger maerial in he 350-plus mesh

range can be recovered beore maerial is sen o setling ponds.

Te producer hen is le o conend wih he 350-minus mae-

rial ha can be mechanically removed rom he eed. A ha

poin, he maerial in a setling pond resembles he consisency

o pain, and polymers can be used o help ulra nes setle.

Te specic graviy o he ulra-ne paricles is so close o ha

o he waer ha i won setle ou on is own accord, Gralon

says. Wihou he use o polymers, removal o ha maerial

rom a setling pond, wheher hrough an excavaor or dragline,

is ypically difcul, labor-inensive work.

o evaluae wha opions will work mos eecively, Gral-

on akes a 10-gallon sample rom he diry waer eed andess i. He hen deermines he bes perorming chemical,

wheher an emulsion or dry occulan would work bes,

and he opimal mehod o adminisering i. Wha ype o

chemical is added again depends on he operaors needs

and how ar hey wan o ake he process. Gralon says ha

some smaller operaions may op or emulsions or simplic-

iys sake. For sies wih a large ow, producers may be more

likely o inves in a dry occulan process wih a polymer

make-down sysem. Once he righ occulan is added o

he setling pond, i bonds o ne maerial, creaing a paricle

comparable o a snowake ha will setle rapidly and comeogeher o orm a more manageable maerial.

And when he proper addiive has been deermined, Gral-

on oers he ollowing advice: i a all possible, mix i wih

clean waer raher han re-circulaed waer and use i in he

recommended porion size. In his case, more is no beter.

A common misake or producers is o add oo much oc-

culan, paricularly inside he clarier where i can sack up a

he botom. Te overriding goal is o keep equipmen such

as clariers clean and operaing properly. I you can pu

oresigh and care ino he mainenance o your equipmen,

you can save yoursel a lo o ime and money, he says.

O

peraors oday have more and beter opions han ever

beore when i comes o dealing wih chemicals andequipmen used or agglomeraion wihin he aggre-

gae indusry. Bob Gralon, presiden and owner o Clearwa-

er Indusries, poins o he developmen o polyacrylamide

occulan as an efcien, eecive, and environmenally

riendly way o setle maerials.

Teyre basically iner chemicals ha can be ied up wih

he solids. Tey snip or all apar wih ime, hea, or sunligh,

so in a sense, hey biodegrade, he says. Teyre no hazard-

ous o sh and he MSDS shees clearly sae heyre sae or

he environmen. Environmenal agencies don have any

hearburn wih he dry anionic polyacrylamide occulans.

On he oher hand, liquid emulsions do conain hydro-

carbons. A producer has o be more careul when using an

emulsion or liquid polymer, Gralon explains. Te advanage

o an emulsion polymer is ha i requires less sophisicaed

hardware o be mixed up in waer and inroduced ino he

sysem. A disadvanage is ha emulsion polymers are less e-

cien, ypically running a approximaely 35 percen acive

versus 90- o 99-percen efciency raings wih dry polymers.

Te dry polymers are much beter, bu he downside o

he dry is ha you need a more complicaed piece o equip-

men o mix and age he polymer, he says. Operaors have o

decide wheher a polymer make-down sysem suis he needso heir operaion in erms o a cos-bene analysis, bu he

resuls can be dramaic.

For example, many producers considering such a sysem

have muliple setling ponds wih coarser maerial such as

sand which alls ou in he rs pond. Finer sil ypically sep-

araes in he nex pond. Colloidal maerial alls ou in he hird,

bu is oen very difcul o exrac in an efcien manner.

When a producer buys a piece o equipmen, buys he chem-

ical, and inroduces i ino his pondyou can lierally ge all o

he solids o all ou o he waer wihin 30 o 40 ee o he pipe

going ino he rs pond, Gralon says. Te polymer binds wihhe sand, clay, and sil, and i alls ou in a homogenous mixure

in he rs pond, eliminaing he need or subsequen ponds. Te

polymer will also bind ha maerial ogeher so ha, i he pond

is cleared airly quickly, i will be easier o remove.

I he operaor wans o ake he nex sep, a clarier can

be added. Anoher opion, paricularly or operaors wih a

lo o coarse maerial, is o consider cyclones and separaors

o spin ou hose paricles. Te maerial ha spins ou o he

cyclone is airly dry and sackable, Gralon says, noing, Te

combinaion o cyclones and clariers is prety atracive o

mos producers.

John Gralton t Bob Gralton t