South Africa

IMSCON 2008

The opportunity to attend the Institute of Mine Surveyors of South Africa conference and give a presentation on Mine Surveying Regulation in New South Wales was a great experience. South Africa is facing many of the same issues that Australia is in regard to Mine surveying. The day prior to the conference, many of the larger mining companies take the opportunity to gather their mine surveyors for a group meeting to discuss various issues. The availability of several of the key Institute members made it possible to hold a brief meeting with them in the afternoon along with President of PLATO (South African equivilent of BOSSI) and the President of the International Society for Mine Surveying to discuss issue effecting the Institute and Indusrty in South Africa, sharing with them some expeiences in Australia.

Thursday the conference proper commenced with a good spread of practical, technical and Institute centred presentations. Tertiary education in South Africa is set to change in the very near future which will have a significant impact on Mine Surveyors. Currently there are two avenues to a Certificate of Competency in South Africa. Diploma or degree in Mineral Surveying from a tertiary institution or through completing the Chamber of Mines exams before sitting the Certificate of Competency exam which are similar to our own in New South Wales, with the exception of Minerals valuation. The future will see the structure of the tertiary education framework change and necessitate a review of the mine surveying courses currently offered and perhaps a move to the certificate of competency being an Advanced/graduate diploma? But its early days.

We think a few roos at the mine is pretty common, these guys get lions and elephants in the car park.

Palabora Mining Company is home to perhaps the largest man made hole in the southern hemisphere, its opencast copper mine. At roughly 2km in diameter, this circular pit is close to 800m deep. Gaining a true appreciation of it's size is hard as there's not much to provide scale. From the photo you can see the shaft head gear in the background which is over 100m high. The benches in the pit are 15m and 30m high which gives some indication also. The photo is taken from the top of one of the mine's spoil dumps that is now a tourist lookout. The pit is no longer being mined as mining relocated underground several years ago to carry on with a block cave operation below the pit. Partially as a result a significant failure of the pit has occured which can be seen in on of the photos. Consequently there is an intense monitoring program of the pit to ensure that any movement is detected and assessed. To do this the mine uses a combination of GNSS recievers, tilt metres, prism monitoring using total station observations to fixed points on structures and trig pillars and photogrametry using a hand held camera and inhouse software will soon be introduced.

The mine borders the Kruger National Park and a trip here is nearly as good as the park, with Elephant, hippo, giraffe, crocodile, lion and many others regularly roaming the site or taking up residency in one of the catchment dams. Baboons are a common pest in the rubbish bins. Safety alerts are regularly circulated advising the location of lions around the mine.

While in town to visit Palabora Mining Company I decided to visit South Africa's largest National Park and drop in on the wildlife.

dozens of Elephants, a leopard, a couple of cheetahs, some hippos, but no lion. Oh well can't have it all, but its quite amazing to be only metres from totally wild animals.

At one time the deepest in the world, but still not far from it. The lowest point in the mine is around 3500m below the surface. Access to the production levels at around 3200-3300m is via a shaft, sub shaft and decline. Rock temperateure is close to 50 degrees celcius and the mine has one of the largest refridgeration plants in Africa to cool the air. This group of shafts has been operating for over 100 years and mines gold using a conventional longwall. At this depth the goaf doesn't stand for long. Development is still carried out using airleg drills, shot firing and clearance scrapers. The ore is loaded at the face by rail boggers and hauled out by rail skip, equipment that we would generally consider obsolete, but it is still used productively here in many mines.

Today presented an opportunity to visit the Mines Rescue Station in Evander, one of three is South Africa. This is where volunteer teams from each of the mines in the district train for typical emergency senarios encountered in Mines. The service has a long and proud history in serving the mines in South Africa and are colloquially refered to as the "Proto" team, a reference to the early breathing equipment that was labelled as a prototype. The name however stuck and is widely use through the country's mines. During the visit I observed two teams completing their quarterly training which today focussed on work load management. The pactical session involved each team member completing the set course and tasks within the simulated mine whilst having their heart rate monitored in real time. The objective was to complete the tasks/course as fast as possible, whilst minimising air comsumption and keeping the heart rate at safe level. All I can say is that experience and fitness pays off.

Matla mines are located near Kriel east of Johannesburg and mine coal using a combination of shortwall and bord and pillar methods. Matla No. 2 has extracted from three seams, with a total extraction thickness in excess of 10m. needless to say that its shallow depth creates a signifficant subsidence impact on the surface which needs to be seen to be believed. Because the surface is grass covered it is possible to obsercethe effect of the subsidence troughs by eye. From imagery on Google maps, the location of the chain pillars pillars can be seen along with some surface ponding. Significant surface rehab also takes place. Subsidence monitoring typically takes place using photogrammetry.

Google maps link:
http://maps.google.com/maps?f=q&hl=en&geocode=&q=matla,+south+africa&sll=37.0625,-95.677068&sspn=35.494074,60.117188&ie=UTF8&ll=-26.201115,29.083643&spn=0.039276,0.058708&t=h&z=14.

Syferfontein was originally an open cut operation named after the original farm that it occupies like many of the mine in the country. The mine operates from a couple of enteries and has mined two seams. Currently the mine extracts coal by bord and pillar method at approximately 5m high by 7.2m wide. No wonder that they make money from first workings! All of the coal is transported by overland belt to Sasol's plant where is it processed to create oil which is further refined to produce petrol. Some 40% of the country's petrol is produced by this method.

One of the production panels utilises a continous coal clearance systems from the miner using a series of loader/conveyors. Surveyors are kept busy setting sights, conducting ribline surveys and completing control surveys as the development rates are pretty good, but they're staffed well, taking up a whole office building. Most mines still use a draftsperson to prepare all their plans and Microstation is a popular package.

With the weekend of, I deceide to venture down to Cape Town to see the sights. I'd been told how Cape Town can be a pretty nasty place if the weather is bad, but I must have jugged it because when I landed the rain had moved on and had been replaced by clousless blue skies and walm days. Cape Town has a rich and diverse history and visitors could spend weeks here learning all about it, but since I had two days, I chose the to biggest draw card to the cape, Table Mountain and Robbon Island.

The cable car to the table of cable mountain is quite a feat of engineering and you can't help but look up in hope that the cable doesn't break. The view for the top is breathtaking, yes the view is stunning but the air at 1100m metres is bloody cold and I could see snow about 50km away, but I was grateful that I had great visiability.

The following day I caught a boat out to Robbon Island about 8km out from Cape Town. Robbon Island also has a long and diverse history, having been used as a lepper colony, military base and most notably as a prison use to house political prisoners during the aphartide era, including Nelson Mandela for 18 years. The tour of the prison is carried out by a former prisoner and can be a moving experience as he explains some of his experiences there. Robbon Island also has a quarrying history from the time when the prisoners were made to cut limestone for the road base and other uses on the island. The whole island is now a world heritage site.

Following an early start, we head east from Pretoria to the Witbank area for my first visit to a South African coal mine. Joining me today is Dennis and Leon, Mine Surveying Inspectors from the Department of Minerals and Energy (DME). Douglas is a bord and pillar mine in the throws of winding down and will cease production toward the end of the year. The Inspectors' task today is to conduct a routine audit on selected roadway underground (typically under highways or other critical imfrastructure), ensuring that they meet design criteria and are correctly plotted on the mine plan along with a general audit of plans. One of the critical areas is the width to height ratio and the intersection dimensions. Douglas carries out first workings in multiple seams where the pillars are overlain with roadways typically in the order of 6.5m wide, Pillar factor of safety is an important consideration.

The inspection involved a conventional chainage and offset ribline survey with additional measurements taken for intersection diagonals and extraction widths. Back in the office this information is plotted along with the calculation of factor of safety and width-height ratio. Provided that these numbers are within tollerance then the inspectors are satisfied. Examination of plans typically highlights areas where the plan does not conform to the standard or reveals an omission.

Following on from the visit to the Platinum mine, the following day I headed out to the site where the world's largest diamond was found, Cullinan. Cullinan is about an hours drive north east of Pretoria and is an otherwise quite country town, surviving on the back of the diamond mine. The mine itself is surrounded by a mining small village, hospital and fire station; it was interesting to learn that during the early 1900's miners would be required to "living-in" in an attempt to control theft. The mine is over 100 year old and has produced a significant amount of the world's diamonds including the largest which was named the "Cullinan diamond" and is now part of the British crown jewells.
Original production was from an opencut that eventually reached 400m in depth, before underground methods were used. Current depth is 800m bellow surface and uses a modified sub level caving method. The shear size and grandure of the mine is nothing like I have ever seen before, with the workshops and lunch room underground being very well apointed and even includes a fish pond.

Survey methods at the mine include real time monitoring of a nearby road using extensiometers and tilt meters, GPS monitoring of the highwall and fine dam, in addition to the typical control surveys, drivage and grade control. Due to the age of the mine some of the original plans for the area over 100 years old and impressive to see especially the draftsmanship, sadly the one thing that modern drafting lacks.

Back to survey reality here as the team consists of a 3 surveyors and 3 assistants. For a while there I thought every mine had scores of assistants.