One Plant Today!

[Carl Zeelie]

Man that's sad......I worked there from 1976 for a number of years. I remember you John.....you were Plant Engineer when I was Production Foreman still. As for how many diamonds Mike....I remember one afternoon shift when we took out more than 11 000 carats...yes eleven thousand in pick ups alone....nevermind the concetrate transported to the recovery! Shared a shift with mining foreman Hugo vd Merwe...so sad to hear of his passing....and in the earlier years Dawie Kerwan and Paul Lisser. Was there the day they got killed in the blasting accident. We were the first to be informed via Chamois radio. I believe the ambulance was overturned on the way thereas wel.....

[Gordon Brown]

For those technically minded folk, No 1 Plant had a headfeed of 90 000 m3 or 150 000 tons per month. It produced 30 000 carats monthly with an average grade of 0,3 carats per m3 and diamond size 0.7 carats per stone. Working costs per ton approxiimated 10% of revenue per ton. The plant consisted of the following sections:
Primary Crusher Section - Hazemag AP7 Impact Crusher
Screening Section - 22mm Lowhead Desanding Screens
Secondary Crushing Section - Hazemag APK 60 Impact Crusher
Milling Section - Six 6.5' Composite Mills charged with steel balls
HMS Section - Two single deck lowhead prep screens; Two Nihard Heavy   Media Cyclones; lowhead sink screens; sieve bends and lowhead float screens; single dech Aerovibe 12mm screen; Cleaning and densification circuit two 36" by 72" Eriez Magnetic Separators; one 66" Wemco Spiral Densifier
Recrush Section - One 48" Gyradisc Crusher over to a 12mm by 3.5mm doubledeck lowhead screen. Undersize to desanding screens.
Tailings Audit Plant - Over a Aerovibe Prep Screen pump fed to a Velco 14" Heavy Media Cyclone to Ferrosilicon Recovery to Cleaning and Densification circuit comprising a 30" by 24" Eriez Magnetic Separator and centrifugal densifier.
Concentrate to drier and X-ray and the hand sorting at sorthouse
Slimes Disposal -2.0mm material pumped to the sea. 

[Carl Zeelie]

Hi Gordon,
You missed the fesi consumption...lol!  ......anyway...the grades were significantly manipulated by the area we mined...10H was specifically very rich and the area where we found "Alladin's cave" also.

[Clint Ebstein]

Thanks for that info it is very interesting

[Gordon Brown]

Carl, No 1 Plant was sited at 10H and the average grade and stone size in the mining block in which it was situated ie the 8H to 13H mining block, was 0.26 carats per m3 and 0.77 carats per stone respectively. Regret unable to remember the FeSi consumption of No 1 Plant!
Kind regards
Gordon

[Carl Zeelie]

Hi Gordon....it was indeed the block where the plant was......I remember blasting at the back of the dump. .....with rocks falling through the offices roof......to minimise rock flying the blasting site was covered with conveyor belting. Caused lots of blockages after it was loaded into the plant. The grade size is correct....I was just wondering whether you were aware of that significant find....made carat call in one evening alone! What happened was that, amongst other factors, a rippertip opened up a cave in the bedrock which was a natural catchment area. I can tell you stories of diamonds streaming onto the concentrate conveyor in the HMS...I even called the Plant Supt...forget who it was Ronnie Potgieter or Jeremy Clarke. One D9 driver made more in pickups than his whole months salary...driver mind you..not even a bedrock cleaner!

[Michael Alexander]

Wow! That must have caused great excitement at the time, was the "cave" closed over? What are the chances that there might be another one or two such "caves" that have been overlooked, after all, it's a pretty big mine....

[Carl Zeelie]

You wish! Jackie Carr spend days afterwards in that site.......I am not privvy to the precise locaion however....was plant Foreman afterall and did not get out into the mine that often.......snuck off with Hugo to the sites every once in a while should the stuff he fed the plant was unagreeable.....magnetite,clay etc

[Gordon Brown]

Carl, I do indeed remember some huge carat production figures coming from no1 plant at some stage. This plant area had some fantastic grades in certain areas. Grades were well above those in the south .The further north one mined the higher the grade and the smaller the stone size. Stands to reason. The smaller stones were carried further along the coast by the longshore drift and the Benguela current
Can you remember the year they found this bonanza?
Kind regards
Gordon

[georg ruf jr.]

Were these pics taken in Irak??

[Carl Zeelie]

Hi Gordon,

I cant remember exactly...its either  76 or 77 ...I remember that there was this huge ashtray level with diamonds........average size about my pinky nail. The mining guys were complaining bitterly...they had to write out slips for each diamond...and it took forever!!!!

[Gordon Brown]

Hi Carl
Carat production for '76 and '77 showed a huge recovery of 66 259 carats in July '76 and 50 617 carats in September '77, well above the monthly averages of 36 507 cts and 32 576 cts respectively for those two years.
Typical Average monthly operating results for 1979 were:
Tonnage Treated                  160 277 Tons
Feed to Sec. Crusher              59 716 Tons
Feed to Milling Section            80 460 Tons
Feed to HMS                         73 767 Tons
Feed to Recrush                    18 719 Tons
FeSi Used                                  28,85 Tons
FeSi Consumption                        0,38 kg/Ton
Feed to Audit Plant                  2 080 Tons
Plant Availability                          75.6%
Best regards
Gordon

[Carl Zeelie]

Hi Gordon,
Sept 77 sounds about right.......

[Carl Zeelie]

Actually no...it was before I got married...so it must have been '76....

[Gordon Brown]

Most probable the 66 000 carat recovery which was twice the planned production.