In a new approach to tackling the skills shortage, Murray & Roberts Cementation is investing in increased capacity at its training centre to allow for greater numbers of students as well as exposure to the true mine environment. Full scale mock ups of shafts, tunneling and production areas, which allow training to be done in a simulated environment, will allow people to train in a genuine, albeit smaller, shaft. "This will allow us to train and place more people in the field and put us ahead of our competitors. It will also reduce the risks and allow for greater productivity. The extensions to the training centre should be completed and operational by August 2007," explains Murray & Roberts Cementation Director of Business Development Allan Widlake.
Safety track records are always high priority, especially when undertaking specialised activities such as shaft sinking. By allowing students to go down a real shaft in a training environment, it is felt that they will be better equipped for the real life scenario, and this will be reflected in later safety assessments.
From a classroom and accommodation point of view, the new facility which currently has a capacity for 100 people will be ramped up to accommodate up to 200 people.
Currently, training for personnel includes initial induction and basic skills. This is followed by specialised skills as and when required. Retraining is then done on an annual basis. Computerized training facilities are also incorporated, where training is done to Mine Qualification Authority (MQA) standards. In today’s competitive business environment, it is necessary for companies to use the benefits of technology to their best advantage.
DRILLING
In addition to the training centre upgrades, and in attempts to further enhance productivity, Murray & Roberts Cementation has recently modernised its fleet of drill rigs with the addition of new Boart Longyear LF230 drill rigs among other machines. Upgrading the fleet was done to improve efficiencies and reduce the lead times to start operations, with the added advantages that production rates are increased. The new machines are currently operating in Rustenburg, Zambia and Ghana.
These machines will allow faster and more accurate accessing of ore bodies for core samples. The LF 230 is capable of achieving at least 1,500m a month of NRQ core to a depth of 2,300m and at the time of purchase was the only machine outside of the US capable of doing this.
Safe Exploration Drilling Methods
Exploring deep-seated ore bodies requires accurate, proven and safe exploration drilling methods. The continued high demand for commodities and the fact that deep-seated ore bodies predominate in South Africa, has resulted in an increased demand for surface exploration drilling.
Deep exploration drilling is a specialist activity of Murray & Roberts Cementation. The company is involved with large amounts of deep and ultra deep exploration drilling and has the capacity to explore to depths of up to 4,000m below surface. This includes a directional drilling, down the hole motor and steering capability which allows for navigation and management of drill holes to customer specification.
Accuracy in exploratory drilling is related to the drilling skills and technology used. Exploration holes are spaced according to a pre-determined drilling pattern and it is essential that each hole stays within a specified cone which makes the accuracy of the drilling operation critical in order to obtain meaningful geological data.
"It is the type of equipment which allows us to drill to maximum depths of about 4,000m, particularly relevant to the gold mining sector, where we have a number of contracts underway with Goldfields, AngloGold Ashanti and some of the junior miners," comments Widlake.
When it comes to deep and ultra deep drilling it is the actual power required to drive the drill string and to lift the drill string and remove the core from the hole which necessitates a large size operation. The type of equipment used for these operations are on site for a far longer period of time than for medium and shallow hole drilling.
Murray & Roberts’ Drilling services encompass both surface and underground exploration drilling as well as directional drilling where customers call on the company’s services to drill inter-level holes for various kinds of activities in the mine including drainage or putting services down from one level to another.
SHAFTSINKING
Commenting on recent technological developments in the area of shaft sinking, Widlake highlights that technologies are aimed at increasing productivity and improving safety. These include the development of an innovative shaft sinking drill rig, which is electro-hydraulic as opposed to pneumatic. This drill rig has the ability to articulate and drill horizontally which allows all the support work in the shaft bottom to be done by the drill rig. Use of this rig will reduce the number of people required at the shaft bottom, thereby lowering the risk of employees’ exposure to falling objects or debris. "From a productivity point of view we believe we will be able to sink the shaft faster," adds Widlake.
Murray & Roberts is currently involved in a number of significant shaft sinking operations.
The Impala Platinum no. 20 shaft is a greenfields contract, and the company is currently ahead of schedule, with less that 200m of sinking remaining. At present the company is gearing up for development work on the project, which, to all intents and purposes, has been a flagship contract for all involved. Handover remains on track for October 2008.
Murray & Roberts Cementation is responsible for the sinking and equipping of a main downcast shaft and an upcast ventilation shaft. Scope of work includes construction of all service infrastructure on the surface, as well as ancillary excavations and access development. The three major players on the project team are Impala Platinum, TWP as the engineering, procurement and construction management (EPCM), and Murray & Roberts Cementation.
In addition, the company has contributed to innovation in shaft sinking through the mechanisation of the blow over process at the Impala Platinum no. 20 shaft contract. The mechanisation of the process, traditionally done using pneumatic hoses with operators, has enhanced safety, lowered the risk of injury by removing people from the shaft bottom. An added advantage is greater productivity.
TauTona Mine is situated on the eastern side of the Western Deep lease area. The scope of Murray & Roberts Cementation’s work in this project is to sink a twin decline system from 120 Level (3,467m below surface) to 128 Level (3,700m below surface). This will allow mining of the carbon leader reef and extend the life of the mine by seven years. The shaft systems comprise a twin decline system 5m wide and 3.8m high with five inter levels and an incline distance of 596m to hoist rock and transport man and material. The declines will be sunk at 26°, which is the same as those recently sunk by the company at Selibi Phikwe, in Botswana. A total of 11,000m of access development will be done concurrent with the sinking of the shafts. The hoist chambers are situated on 120 Level which is approximately 3.5kms from the three vertical shaft systems. Site establishment started in January 2004 and mining operations in March 2004. Project completion is scheduled for January 2012.
Site has been established and construction has commenced at Paardekraal # 2. This is a twin shaft system for Anglo Platinum in the Rustenburg area and Murray & Roberts Cementation will be responsible for the sinking of the twin shafts and the associated underground infrastructure which will include the necessary production levels, all the loading levels, pump stations, dams, settlers and underground silos. There will also be a decline system connecting to Paardekraal # 1 Shaft. All work will be done simultaneously on this three year contract.
Shaft sinking is still underway at Harmony’s Doornkop gold mine on the West Rand where deepening the main shaft is being done. This project commenced in May 2003 and includes the deepening of the main shaft from just below 132 Level to a new shaft bottom just below 212 Level. This is a total sinking depth of 830m. The contract also includes the upgrading of the sub vertical ventilation shaft to increase hoisting capacity. A combination of raiseboring and slyping is being used on the main shaft simultaneously, with the bottom of the shaft being raisebored and slyped with blind sinking at the bottom, which is unique to this project. These activities are being done simultaneously to shorten the programme and allow faster access to the ore reserves. An important aspect of this contract is that existing mining activities are continuing without disruption, and this has required careful planning.
Murray & Roberts Cementation is in the process of completing the Karee No. 4 shaft for Lonmin platinum. The shaft has been sunk to the bottom, and equipping of the shaft and stations is now taking place. This contract follows on the successful completion of the sinking of the Karee #3 shaft.
Murray & Roberts Cementation has started on the refurbishment of the Crocodile River Mine vertical shaft. The company is responsible for re-equipping the existing 550m deep vertical shaft, blasting and equipping a belt level, and a pump chamber, as well as mine-water settling facilities. This shaft, which was sunk almost 20 years ago, is in excellent condition, and timeous completion of this project will fast track the mine’s expansion. Murray & Roberts Cementation is tasked with completing the declines up to 3 Level, and establishing 24 months of ore reserves. The contract began in July 2006, and is scheduled for completion in June 2008.
The company is also in the process of doing refurbishment at Simmer and Jack’s Ezulweni Shaft. This contract involves the replacement of shaft steelwork and services in the shaft to allow full production to take place. This is a short-term contract which is due for completion by mid year.
Murray & Roberts Cementation is also in the process of completing the Turffontein decline system for Anglo Platinum.
Shaft sinking work in the coal fields includes a ventilation shaft for Goedehoop Colliery in Witbank. This shaft will be blind sunk and completed by mid year.
Shaft sinking contracts that are due to start include the raiseboring of three ventilation shafts for Anglo Platinum’s Townlands mine on the Western limb. Murray & Roberts Cementation is the appointed contractor on this project.