AT AMANDELBULT WE MAKE EVERYTHING WORK

Transcription

1 AT AMANDELBULT WE MAKE EVERYTHING WORK

2 Room and Pillar Mechanised Mining at a Semi-steep Dip. Presented by: Thomas van den Berg

3 Presentation format Why Room and pillar using TM3 Where and how it originated How do you mine at an 18 degree dip The machines, concepts and principles Future frontiers Questions

4 "TELL ME AND I WILL FORGET SHOW ME AND I WILL REMEMBER INVOLVE ME AND I WILL UNDERSTAND" At Amandelbult we make everything work- 4 LIFE

5 Safety issues Roof bolts Recirculation Roadway conditions Rubber tyre s Machine conditions Amandelbult- 4 LIFE

6 The Intent of the project To successfully mine a 1.3m UG2 reef Semi-to steeply dipping (18-20 degrees) Using mobile machinery travelling on apparent dips (9-12 degrees) Using throw blasting Techniques Smart bolting as support. Location On the Ug2 at a head grade of 4.37g/ton One below the Bierspruit river (8WTM3) The other on the Eastern section at 43E (43ETM3).

7 Picture--with quote My grandfather once told me that there are two kinds of people, those who do the work and those who take the credit. He told me to try and be in the first group, there was less competition there. Indira Ghandi

8 Why trackless Mining? The R rrrrrrrrrrrrrs of TM3 Reduced risk? Revenue? R/ ton? Required skills? Recent Technology? Recent market demand? Rejuvenate productivity? Reduced off-reef development? Severity?

9 Why room and pillar? The 8W area -restricted panel lengths Increasing Amandelbult s tonnage capacity Faster ramp up, to increased production. Modernised, and a human friendly Reducing mining costs -in a commodity market where we remain price takers -in a volume driven industry Incorporating of long hole drilling, smart bolting and rock on floor throw blasting

10 Low Profile Single Boom Drill Rig

11 Where did it all begin? Discussions with Dr. Morris Strategic Planning- seeking new mining layouts Visits to Poland Visits to Bleskop, Kroondal, X-strata, Union Visits to Thornecliff,. Combining Longhole stoping and room & pillar Throw blasting, Rock on floor, Opencast techn.. Smart bolting techniques,.. Existing 16W reef decline, within a restricted...

12 Low profile roofbolter

13 How do you mine at an degree dip? Mining at an apparent dip Sweetening the pot Pre-development Knowledge of UG2 from Merensky Footwall at 1 g/ton

14 Chromite hanging wall showing good horizon control

15 Trackless Layout (Macro) 4 Declines on Reef at 9 degrees. One ingress, the other egress. Outer declines for ledging Stope drives at 5 degrees above strike and 2 degrees up. Develop intake and return airways. Decline 2 -Main Belt Decline. Stike Belt Drives to serve 5 Stope Drive.

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17 Trackless Layout (Micro) 4 Meter wide Stope Drives with 2 meter shoulder Reef Cut. Cut F/Wall to create a 12 degrees slope. Drive stopes to end and then drill stopes on retreat Cut Pillars on Reef width - Squat pillar formula. Throw blasting is used to extract Reef from pillar position. Vent holings as required- 5th holing Water-jet out no go zones Retreat vamp roadways-stopes.

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27 Low Profile Single Boom Drill Rig

28 Dilution % Development No. 1 Decline No. 2 Decline No. 3 Decline No. 4 Decline Total Dev Decline Ledge Holings Total

29 Dilution % Stoping Stoping Strike Drives 2m Ledge Strike Belts Belt Holings Sliping Total

30 Dilution % Total Project Stoping Development Total TM³ Conv. 14m Panels Conv. 35m Panels Conv. Total

31 Low Profile LHD

32 The Fleet 2 x Aardmaster (Drill Rig). 6 x Aardvark (L.H.D.) 2 x Utility vehicle (Transporter) 1 x Roofbolter (Support Drilling) 2 x Supervision Vehicle (4x4) 1 x Diesel & Lubrication Cassette 1 x Emulsion Explosive Cassette

33 Low Profile Utility Vehicle

34 Concepts and principles 3 Cycle operations, continuous mining. Maximise Drill Rig capability, 4.3 meters. Minimise tramming distance and handling L.H.D. s in conjunction with conveyor belts. Handle ore once Rock on floor concept (SMX). Long hole drilling and Throw blasting. Emulsion and EDD s.

35 Throw blast zone Throw blast zone 0.75m 1.25m 1.25m road 1.3m 1.5m 1.5m 1.2m Roofbolts ledge Reef Throw blast zone

36 Concepts and principles Maintenance Repair Contract- supplier Repairs and daily maintenance done at machine Canopy protection, no foot on footwall No go zone s Clean mining Hot seat change-overs Smart bolting / Spin to stall

37 joint Horizon control problems harztbergite Bolting standards?

38 Understand failure mechanism Using an effective support system Design by measurement Monitor the performance

39 10 Outcome of mining using AVERAGE support Amount of support 5 FOG using average support average support Support required to prevent FOG 0 mining advance

40 Amount of support Smartbolting can be safer and more productive Increased support in areas were additional support required average support Reduced support in Good conditions mining advance Smartbolting

41 Spin to stall resin rock bolt System All the materials and bolter performance must be correctly specified otherwise it wont work! If it doesn t work there is something wrong with the bolter machine or the materials! It is a system if you change one element it will probably fail! Requires training for operators, supervisors and rock engineers.

42 SPIN TO STALL retaining cap Installation tube 1 Stop on drill rod thread showing Hole ~100mm shorter than bolt drilled to fixed distance Correct quantity of resin inserted to ensure full the back of hole Thrust and spin until bolt is fully inserted When bolt reaches Back of hole stop thrusting but DO NOT STOP SPINNING BOLT Shear pin breaks as resin hardens and bolt tightens to roof. Installation complete SEQUENCE FOR INSTALLING A SPIN TO STALL ROCKBOLT

43 Low bond strength resin rockbolt system

44 R M T Rock Mechanics Technology A stiff bolting system will not pull out

45 Low Profile Single Boom Roofbolter

46 Final check on the system. If it doesn t move it can t fall. Tell tales proven. Other solutions possible.

47 How a single height tell tale works

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50 Shear failure

51 How an extensometer works mm 60

52 Proposed scheme for 16 West room and pillar project Design by measurement based on spin to stall bolts. In areas of concern install alternative support. Monitor routinely and take action accordingly. Equipment shown to be sensitive to very small movements. Extonsometer will TELL YOU HOW HIGH THE HANGING WALL IS MOVING and therefore the length of bolt required. More extensometers required in areas where movement likely e.g domes in wider openings. Assess hanging wall prior to throw blasting.

53 Proposed initial bolt pattern for production drives harztbergite 1.2 m UG m 2.1m 0.75m 4.0 m 1.6m UG2

54 Requirements for rockbolts Prevent hanging wall movement. Must be stiff system. Coverage to prevent block fall out. Maintain hanging wall stability on development and after sidewall blasting. Simple to install correctly difficult to install incorrectly. Able to assess quality control. Rapid installation using mechanised and hand held bolter.

55 Future Frontiers

56 Challenge ahead To reduce injury ratio s To reduce costs to R65/ton - shaft head cost To increase productivity to 500 tons per TEC To control dilution To improve our planned maintenance systems Retention of skills and correct training Manage life expectancy of machines Dealing with geological anomalies Rand dollar exchange exposure

57 LHD Productivity Production Rate Versus Tramming Distance at 12 Degrees Dip Production Rate [t/h r] One Way Tramming Distance [m]

58 Suspended Conveyor Belt If everybody is thinking alike, then somebody isn t thinking. George S Patton, Jr.

59 Costs Thanks Questions