Ruby Mining at Naberera

Executive Summary.

In february2017, Mr. Sayore acquired a Primary mining license allowing him to start prospecting for gemstones at Naberera, Simanjiro district and Manyara province of Tanzania. To carry out the operation, a thorough analysis and planning was proposed and accepted as follows;

• Visit and examine the prospect sites at Naberera,
• Examine some workings in the area and neighboring mines as permitted, practical and safe to do.
• Assess the needs and make recommendations for methods of working, ventilation and hoisting;
• Assess any written or verbal records of past workings, production etc. and current geological data so as to prioritize (select target) areas for mining.
• Assess infrastructure facilities and needs and make appropriate recommendations with respect to electricity, water, compressed air, roads, fencing, explosives acquisition and storage,
• Make recommendations for security protection and transportation of mined gemstones;
• Consider the chances of the gemstones to mechanical recovery from surface soils or gravels and from surf ace and underground host rocks;
• Compile a development plan and schedule for gemstone mining,
• Compile capital and operating cost estimates for that plan.
• Compile technical guidelines for the conduct of the plan.
• Compile a cash flow projection for the plan.
• Specify what further geological or other works that may be necessary to either justify or improve upon proposals made here.
• Incorporate the above into a report to Mr. Sayore.

 

 

Introduction:

Mr. Sayore is a licensed miner in Tanzania and has been involved in mining and trading for gemstones found in Tanzania for some time now. The gemstones mined or those bought from other miners are exported worldwide.

Mr. Sayore has been involved in the exploration and moderate mining of Tanzanite in Mirerani and green garnet (Tsavorite) in Lemshuku for a few years.

Mr. Sayore wishes to start serious mining for gemstones in his Naberera Mines at Simanjiro district of Manyara Province. Based on the new government policy of well designed, planned and safe mining, Mr. Sayore employed the service of a Mining and Geological Consultancy, whose directors are well experienced in gemstone mining in Tanzania, to produce technical and cost estimates for a safer and efficient conduct of mining operations in the Naberera region.

BACKGROUND.

• Location.

Naberera mining site is situated about 150 km south East of Arusha City. Access to the mining area is through a tarmac road via the Kilimanjaro International Airport to Mirerani, and a non-graded dirt road through Terat town. The road from Arusha to Naberera is an upgraded road passable all the year through. Arusha, which is the regional capital town, is 40 km from Kilimanjaro International Airport with daily flights to Europe, Dar es Salaam and other parts of the country.

• Topography

The prospect landscape comprises a number of hills including the lelatema, Oldonyo Lalasho, Oldonyo Ngigo and Oldonyo Legament.  These hills rise up to 4100 feet above sea level. The hills have a dry climate such that there is little, fluvial influence upon immediate area from these hills, there lies plains with little cultivation supporting grasslands and thorn bushes. The hills support thorn bushes below and further up only sparse ground cover with bushes and grass Due to dryness of the area, especially the hills, the countryside is largely uninhabited and is still occupied by some wildlife species.

• Water and Services.

Water is available at around the camp area markets from shallow wells. The plains may be able to provide water from boreholes in the future. There is no Main Grid electricity supply in Naberera or at the actual mining site.

1.4       Population

As mentioned above, the countryside around the site is generally uninhabited except for a few nomadic Maasai people. A substantial number of miners reside in the area working in other mines in the area and supports a substantial population to support mining activities. Labor may also be available from Arusha town, Mererani and Lemshuku areas.

2.0       GEOLOGY.

The Naberera; lelatema hills complex is part of the preterozoic Mozambique Belt of East Africa. The basement system rocks have been dated at between 800 million years and 1.2 billion years of the Usagaran rocks in northern Tanzania. They consist largely of orthogneisses and paragneisses interbedded with mica, kyanite, and graphite schists, with lesser amounts of quartzites, calc-silicate rocks, and crystalline limestones. It is the presence of these crystalline limestones with graphite gneisses which compound the development of Tsavorite garnets, as well as other Mozambique Belt gemstones, especially Ruby. Crystalline limestones, usually coarse-to medium-grained and white to grey in color, form the high ridges on these hills. The crystalline limestones are dolomites. Graphite is commonly disseminated through the crystalline limestone. Several silicate minerals are relatively common in these rocks, including quartz, plagioclase muscovite diopcide and grossularite. The graphite gneisses are only locally abundant interbedded with crystalline limestones, which is ideal for gemstone formation. These rocks typically strike north-northwest and they dip to the east at 45° to 60°. Structurally, the area is dominated by a series of folds overturned toward the west and plunging northward. The graphite gneisses consist of quartz, alkali feldspar, biotite and of course graphite. Sillimanite, epidote, allanite, sphene, zircon, apatite, hematite, and magnetite are common accessory minerals. It is interesting to note that Ruby, Tsavorite, Tanzanite, Tourmaline and other gemstones in the area occur basically in the same geologic environment and are in association. It is rare, however, to find both of these gem species together in gem quality. Ruby occurs in what are called nodules or “potatoes” which are found in what Bridges called “ore shoots” These are shoots occur in horizontals within the graphite gneiss, close to, or in contact with, crystalline Limestone. Folding or faulting of the, gneiss tends to increase the probability that the gemstone nodules will occur. Once these potatoes are intercepted, as much gem material as possible is collected at the face for further close check up on surface.

Resource Potential

For most gemstones, a realistic resource or reserve quantification is difficult to make. However, it should suffice to say that Ruby, Tsavorite, Rhodolite, Tourmaline and other related gemstones continue to be produced from mines being worked in the area. Principally a Scottish geologist named Campbell Bridges first mined Tsavorite garnets in 1968 in Lemshuku area while Tiffany and Co. began mining of Tanzanite around the same period. Since then production of this gemstones has continued from the areas to date.  Historic production in the Naberera pits which are still productive, show that there is a large potential for alluvial Tsavorite, which may make a small Heavy Media Separator ( H.M.S) plant economical.

 

 

2.2 Site selection

An open pit for alluvial Ruby and Tourmaline have been located on an area prospected to hold abundant reserves. One place has been earmarked for surface operations.

 

3.0 MINING HISTORY.

(REQUIRED FOR RUBY)

 

 4.0 MINING PROPOSAL.

 

4.1 Open Pit versus Underground.

Mining will take into account geology and geotechnical considerations. However as mentioned earlier, small scale open pit mining is recommended in the areas where there are prospects for large reserves. In other areas underground mining offers a great chance of finding the nodules or potatoes by hard rock mining.

 4.2 Method and Layout.

To begin with, we will undertake open cast mining to collect the reserve that is close to the surface before proceeding to use deep shafts to reach reserves that are deeper into the earth. A layout based on tunneling following the marker planes, with regularization of the layout, the use of support where necessary and safe practices making a room and pillar arrangement is proposed.

A shaft will initially be sunk in commencement of the deep shaft operations. The shaft will incline with 2m x 2m dimensions. This shaft will be used for passage of personnel and other services. The shaft will be sunk on the hanging wall so as to be able to intercept as many marker planes as possible. The marker planes are essentially the “ore shoots” as Bridges call them. These ore shoots occur in horizons with the graphite gneiss, close to or in contact with, crystalline limestone. The service shaft will be a ramp inclined at 50° and proceed in a spiral design.

The shaft will be sunk to a depth of two hundred and fifty meters, (250m) the lowest point expected to have ore shoot.

During sinking of the shaft, it is expected that several ore shoots will be intercepted. Once an ore shoot is intercepted, an inclined shaft following the dip of the ore shoot will be developed from the ramp. This shaft will initially be used as an exploration winze for approximately thirty (30) meters any signs of the presence of green garnet within that distance will indicate that the ore shoot is productive.

 

If while sinking the exploration winze, signs for the presence of gemstones are clear, or a potato is intercepted, another inclined shaft, at approximately the same angle as the dip of the ore shoot, will be developed. This shaft will be developed five (5) meters below the exploration wince. The shaft below the exploration winze will be used for hoisting of material from the exploration winze and associated drives.

Horizontal tunnels will be developed from the exploration shaft perpendicular to it in both directions. The horizontal tunnels will be developed within the ore shoots ten (10) meters consecutively. These horizontal tunnels will be used to create the room and pillar arrangement in a retreat mining system. Rooms of widths up to 5m with 1.5m pillars will be created.

 4.3 Drilling and Blasting.

 

This is one aspect in which productivity can be greatly improved relatively cheaply. Drilling will be done using rotary percussive hand held rock drills with air legs, and axial water flushing. Such equipment is readily available in Arusha City and form suppliers around the nearby mining areas.

Standard chisel bit drill steels in the range from 0.5m long to 1.2m long should be used the range from 0.5m long to 1.2m long should be used. Bits with diameters range from 0.5m long to 1.2m long should be used. Bit diameters in range 28mm to 32mm will be sufficient for 25mm explosives available in the market. Drill steels should be sharpened at the end of every shift on an air or electric powered grinder.

Assuming cross sections of about four meter squared are used, about 25 holes pattern covering the area should be adopted to start with, and modified according to results. The objective is to break the rock into movable fragments without damaging the sidewalls, while excavating the desired prolife.   Holes with depths of around 1.2m will be ample and should minimize drill holes straying into sidewalls.

Once drilling is completed, the holes will be cleaned using a combination of compressed air and water. The holes will be charged using 25mm fracture explosives. These may be magnum boosters or Super dyne depending on which is available. Experience has shown that one piece of the above explosives topped with ANFO is sufficient per hole to produce desirable results. However such a combination is good in places where no production is expected. In places where green garnets may be produced, only magnum boosters or super dyne should be used. The use of ANFO has shown to cause undesirable fragmentation of the rock and gemstones in similar geological situations in Mererani and Lemshuku.

Detonation would be most safely provided by using capped safety fuses, igniter cord and delay starters Short period delays (SPD) detonators may also be in place of capped safety fuses. All standard precautions to avoid: short circuits, static and lightning events and premature detonation due to wrong loading procedures must be observed.

Due to the small diameter of the blast holes as well as the angle, which may sometimes be horizontal and even inclined upwards, it will be difficult to pour ANFO into such holes Therefore, plastic tubes/bags around 25mm diameter will be used to load the ANFO and stemming material into the blast holes. The ANFO and stemming material will be loaded into the plastic bags/tubes on surface The plastic bags/tubes will be cut in short lengths around 200mm to resemble explosive cartridges.

Explosives storage and handling is subject to strict legal controls, a magazine could be built near the site. Licensed explosive storage boxes will be sufficient for the projects.

4.4 Support

Inspection of operating and old underground mines in nearby mines at Mirerani and Lemshuku has revealed that the rocks are generally stable for the 2m to 5m span normally present requiring little or no support. The workings that have been observed appear sound when in the bedrock; restricted in span and abutted by smooth sidewall continuity.

These conditions maintained, and in the absence of thin partings between workings. The layout pillars should prove adequate. It is an established and logical fact that maintaining a smooth single bedding plane wall surface is a most critical contribution to maintaining stability and reducing artificial support costs. This means avoiding sockets in the sidewalls and avoiding “goose chase” deviations of the tunnels across the bedding.

However despite the above, safety must be of utmost importance always. Therefore timber poles should be used to support brows, and should be used with plank headboards when the bearing surface is blocky. Rock bolts should be on hand for the anchoring of identified or apparent discrete blocks. Wire mesh may have to be used with poles and/or bolts when the surface is very friable. Hardwood is preferred to be used for support where timber is needed.

As mentioned above, safety must of utmost importance. Therefore safe working practices must be adhered to at all times. This means:

• Before start of work at any face or any other part of the mine the team leader must make sure that the place is safe for people to work. Loose rock fragments must be barred down.
• Each miner must watch the condition of his surroundings throughout the shift.
• Explosives must be handled with the care they deserve.
• Safety education and awareness must be given utmost priority.

 

4.5   Loading and Tramming.

.

Manual loading using hand shovels will be done. In the hoisting shaft, broken rock will be hand shoveled straight into the skip. For most part, the service ramp will be developed at a raise from the hoisting shaft; hence broken material will fall by gravity to a point where minimal hand shoveling will be done prior to loading into the skip.

For the inclined exploration shaft with the associated inclined hoisting shaft, broken rock will also be hand shoveled into the skip in the hoisting shaft. As for the horizontal tunnels, broken rock will be hand shoveled into wheelbarrows. The wheel barrows will be pushed manually to a loading point above the inclined hoisting shaft where the material will be loaded into the skip manually.

With time having established the productivity of the ore shoots, laying of rails and half ton hand tramming hoppers may be introduced in some of the horizontal tunnels. Hand shoveling of broken material for some distance may be unavoidable in some cases before loading into a wheelbarrow or skip. However given the relatively low labor rates, this should not be a problem although this may be at the expense of security and safety due to increased number of people underground.

4.6 Hoisting

An electric hoist will be installed on the surface of the shaft with a capacity of 5tons.A skip with the capacity to carry 2 tons will be used in this shaft. At the shaft bottom, or level being worked on, a platform should be constructed using timber planks 50mm x 150mm and angel iron bars or rails fastened to the rock by bolts in drilled holes. A timber/steel plate loading slide will be arranged so as to swing down to the lip of the skip from a raised mound.

At the surface (collar) a similar platform should be fitted with a hole for the skip and a swinging timber discharge chute. These will be beneath the hoist sheave suspended from a steel head frame with a7m headroom from sheave axis to the ground. This arrangement will allow skip to be tipped to pour the rock down the chute into a manually hand pushed pan running on rails. The pan will be pushed to a sorting platform if it is carrying ore, or to a waste dump if it is carrying waste. After the skip has tipped its load, the chute will be swung away for the skip to return to the working level.

A signaling system to control skip movements in the form of good electric bells will be installed. No personnel will be allowed to be in the hoisting shaft while the skip is in motion. Personnel involved in loading broken rock into the skip must leave the shaft before signaling for it to ascend or descend. A code will be introduced with an acknowledgement system for safe movement of the skip and personnel. The working condition of the system must be checked each shift.

 4.7 Sorting and Disposal

A sorting area made of a concrete fenced slab 20m x 20m will be constructed close to the hoisting shaft. Ore shoot material from underground potentially containing nodules or potatoes will be· trammed to the sorting area. The sorting area and the waste dump will be constructed in opposite sides of the hoisting shaft for easy of movement of the hand pushed pan.

On the sorting highly guarded slab, oversize rocks will be broken using sledgehammers. Material from ore shoots can easily be broken using sledgehammers. Breaking of the oversize material will be done carefully so as not to smash any gemstones present. In the breaking process the oversize material will be carefully checked for presence of gemstones. Water may be required to wash the rocks of dirt.

Undersize material will be sieved manually to remove the minus one (1) mm material. This will be achieved using sloping sieves onto which the material will be hand shoveled and allowed to fall down the sieve. Plus one material will be thoroughly checked for any gemstones. Mechanical sieves and jiggers may also be used.

The material which has been checked for presence of gemstones will be dumped separately at a low-grade ore stockpile. Ruby has a specific gravity around 3.97-4.08, which makes it amenable to gravity by dense media methods. Therefore it is prudent that, the shoot material be checked manually for gemstones,  be separately stockpiled, such that if in future if a mechanical concentration method is employed, it will be easy to process this material. As mentioned earlier a mechanical concentration method needs a separated study to see its economic viability.

4. 8 Man way Access

Personnel will access the underground workings via the inclined shaft/ramp. This will be fitted with wooden pillars of sound construction well anchored to the rock walls. From this inclined shaft/ramp, men will access the ore body through the inclined exploration shaft, which will also be fitted with wooden ladders in the same manner as in the ramp.

4. 9 Ventilation and services.

Natural ventilation should he sufficient for the initial stage, as two shafts will be -sunk at the same time with connecting tunnels at short distances from one another. Clearing of fumes after blasting may be done using compressed air if necessary, with depth natural Ventilation may not be sufficient and such mechanical ventilation methods must be employed.

Exhaust fans 0.3m, diameters with ducts will be used to supply air to working faces and for clearance of fumes after blasting. The fans and ducts will be installed in the inclined. shaft/ramp. At a later stage depending on economic viability based on the practical production from these mines, a third shaft will be sunk for ventilation purposes only. This shaft will be provided with exhaust fans on surface.

The mine will have a compressor with a capacity to supply air for at least four (4) hand held rock drills, thus about 600cfm (0.30 m cubed per second) at about 8 bars which is 6.5 bars at the drill.

Drilling will require water at about 5l per minute (0.3m cubic per hour) per drill at a pressure slightly lower than the air pressure, say 5 bars.

Thus drilling will require about one ton of water per drill per day (about 3 hours drilling per day) supplied from at least 50m above the face. This will be achieved by constructing concrete tanks in one of the hills near each mine. A 30m cubed capacity tank will be sufficient for drilling and other activities requiring water at the camps. A 10m cubed water capacity tank making three trips to Terat will fill the tanks. This can be achieved in one day. The water bowser may need to top up each tank twice a week or as it may be required. PVC pipes, 25mm in diameter will supply water underground and elsewhere. Further studies to see the possibility of drilling boreholes for water nearby are recommended.

Compressed air will be supplied to the underground workings using 50mm PVC pipes installed in the service shaft/ramp. 25mm PVC pipes will be the take-off pipes from the main pipe in the ramp to working faces. From these pipes, 17.5mm high-pressure hoses at least 1Om long, will supply air to the drill. The main air pipes will be encored to the wall in the service shaft. A 20mm long galvanized steel pipe will be used as a take-off point from the compressor to reduce air temperature before it reaches the PVC pipe.

The drills will also need an on airline lubrication. This will be provided for by an oiler located 3m from the drill. The oiler must be checked for oil at the start of each drilling shift.

Electricity will be supplied to the underground workings for lighting, fans, hoisting in down-dip inclined shafts, as well as other equipment that use electric power. On surface electricity will be required for the hoist on the main hoisting vertical shaft, night lighting, lamp charging, drill steel sharpening, welding and other electrical tools. An electric generator in the 0rder of 60KVA is recommended for each mine; if the compressor available is also electric driven, then electric power requirements will be higher.

The Naberera area is generally dry with little rainfall; therefore little problems will be encountered due to rainwater. However although not experienced in any of the other mines the area, underground water in small quantities may be experienced. Therefore small submersible water pumps must be at hand. The pumps will also be used to pump out water from drilling operations. 25mm PVC pipes will be used for pumping water out of the mine. These pipes will be encored on the wall of the service shaft. On surface, the shaft collar lip will be raised slightly to prevent any flash flood rainwater runoff from channeling into the mine.

Transport will be required for the supply of consumables such as timber, food, fuel and other items to the mines from Arusha. This may be achieved using 5 ton ex-army four-wheel drive trucks, preferably with a built in winch. Transport will also be required for supervisors to move from Arusha to the mines and other areas as may be required. A four-wheel drive pickup will be desirable. A utility vehicle will also be needed for transport of small things such as explosives. This may be provided by a four wheel drive pickup. A 10 ton water bowser truck will be required for water supply from Mirerani Town to the mines.

4.10 Survey and Professional Services.

Proper survey using a Theodolite with its accessories will be required during shaft sinking and tunneling. Survey control will be required for positioning, direction and level of the shafts. A surveyor with his/her crew will therefore be needed at the mines all the time.

Geological services will be required from the start in order to study and record all geological data from the early stages. Geological services will also be required in identifying the ore shoots as well as studying which ones are more likely to be productive. A qualified geologist, preferably with experience in gemstone mining in similar geological settings will be needed. His crew must include people with vast experience mining around the region; advice from them will be of great value.

 

 4.11 Production Output

The initial stage of mining in each of the mines will involve sinking of the main vertical hoisting shaft and the inclined service shaft/ramp. Very little or no ore material is expected from these operations. Waste tonnage from these operations will be 4 for the hoisting shaft and 5 for the service shaft per blast. This will result into 9 tons blasted per day, with one drilling shift and two cleaning shifts working 22 days per month (five days per week allowing Saturday a half day for other activities). This will result into an advance of 22 meters per month per shaft.

The inclined hosting shaft with the associated inclined exploration shaft will have the same dimensions as the ramp and yield the same tonnage as the ramp per blast; once development of these starts, the tonnage blasted per day will be 9 tons from both the two faces. Tonnage blasted from stopping operations will need to be controlled at the time to be in line with reasonable sorting speed and security.

Based on the discussion held with experienced owners of Green Garnet pits in Lemshuku, a grade of 0.2 to 0.5 gram of gem quality green garnet per ton may be assumed. Although the existence of nodules is erratic and hence the production, however an average grade over 30m to 50m advance in an ore shoot averages out into 0.2 to 0.5 gram of gem quality Tsavorite.

For the purpose of this report the lower average production of 0.2 grams of Tanzanite per ton of ore mined will be used. High production averages are expected.

The shafts will be positioned such that the first ore shoot will be intercepted at 40m ventricle distance. According to the mining schedule proposed, shaft sinking will start in the fifth month hence production will start in the eighth month.

 4.12 Safety Summary.

As safety is of utmost importance, and also due to the fact that it has not taken such importance in surrounding mines in the area, safety points mentioned above and some additional ones are summarized here:

• All staff must wear hard hats, overalls and cap lamps underground.
• All workings to be inspected by the supervisor at the beginning of each shift.
• All staff to adopt responsibility for their own safety and machinery at all times.
• All faces to be inspected for and cleared of misfires before drilling.
• All rock surfaces to be physically barred before work commences.
• Safety belts fastened to solid anchorage to be worn while working over drops.
• No men in hoisting shaft while skip is moving.
• Artificial support to be inspected regularly and replaced if necessary.
• All explosives to be handled according to regulations.
• All blasting to be done at formally planned times after clearance of all personnel from underground.
• At least one hour to be allowed for fume clearance.
• First aid kits to be provided at strategic and easily accessible places underground.
• A dispensary for the mines, with one clinical officer and a nurse must be provided.

The list above cannot be considered to include everything, further rules must be made and enforced for the safe operation of the mine according to the equipment, practices and methods that are adopted and developed.

4.13 Security.

With large values concentrated in small and infrequently discovered nodules or potatoes of gemstones, lax security for any length of time may lose the company stones of high value.

Security will depend on all senior personnel including the owners plus a number of security staff. Security personnel on duty will check other staff and among themselves, routinely but irregularly. Rather than as an atmosphere of distrust, this must be adopted as a policy of mutual trust maintenance, and applied to all staff from the owners downwards.

Fencing, with patrol inspections of the site will form an outer ring. An inner chain link fence enclosing the underground workings must also be erected. The area within the inner fence must be well lit at night. A gate cum changing house with bathroom should straddle this fence and contain mine side and outside changing rooms so that there is no need for non-mine clothes, effects or equipment to come into the mine site at all. Staff and visitors will then effectively enter the mine side changing rooms naked before donning pocket less overalls. The shift supervisor should first inspect each blasted face before cleaning commences so that potato discovery is made as early as possible. Thorough _ checks must be done to any equipment, which leaves the site; this should be kept to the minimum.

The sorting slab must be guarded 24 hours a day. While sorters are working, senior personnel with at least two security staff must be present. The sorting slab will be constructed within the inner fence of the underground workings.

Security matters will place a considerable responsibility on the shift supervisor and shift security chief, who must therefore be accompanied and/or checked upon at frequent irregular intervals.

Gemstones discovered at the face, should be collected separately in lockable tarpaulin bags, and taken directly to the double locked mine strongbox within the enclosure at the end of each shift. Gemstones found at the sorting slab will also be collected in the same manner. The mine strong box should have a one way-posting box, such that stones may be deposited even if the two key holders are not present. The handling of the gemstones therefore will be open to the scrutiny of all key holders. These stones may be transported to Arusha for cobbling and grading frequently but irregularly. Neither the above nor any other procedures can infallibly prevent theft, but they should minimize the risks, further procedures should be adopted as affordable and seen fit. Whatever is implemented, it is important to avoid settling into a predictable routine.

5.0 STAFFING

5.1 Numbers.

Senior and professional personnel will work alternately for both mines. These will be as follows:

Mine manager                                                    1

Mine Geologist                                                  1

Stores and accounts clerk                                  1

Drivers and mechanics/electricians                   2

Chief security officer                                         1

Total                                                                   6

Other staff required for each mine will be:

Designation

Day

Afternoon

Night

Total

Mining Department

Mine superintendent	1	–	–	1
Shift boss	1	1	1	3
Drill operators	4	–	–	4
Lashers	–	3	3	6
Hoist operator	2	–	–	2
Sorters	2	–	–	2
Geological helpers	1	–	–	1
Cooks	1	–	–	1

Security Department

.

Shift commander	1	1	1	3
Security Guards	1	1	1	3
Total	14	6	6	26

Conclusion and Recommendations.

The following comments can be made without implying any prediction quantity and quality of gemstones produced. This can be made from the past mining experience from other Primary mining license holder in the areas, although even where known it is not necessary a guide to the future.

It is recommended that open-cast mining operations to be carried out for Mining operations at the Mine for starters and deep shaft mining will follow up on a second phase.

For deep shaft mining, a shaft will be sunk in the mining block. The shaft will be inclined at 50 degrees spiral. The shaft will be sunk down to 250m below surface. During shaft sinking wherever the reef is intercepted, winzes will be developed to exploit the gemstones in it.

Drilling will be achieved using pneumatic rotary percussive hand held rock drills and axial water lashing. The bit diameters required will be in the range of 28mm to 32mm, which are ideal to 25mm explosive cartridges. Hoisting will be done using electric powered hoists. This operation will require at least 30 employees.

It is estimated that the project would require capital funding of USD$ 850,000 for open cast and deep shaft mining. Mr. Sayore is seeking for a joint venture partnership to undertake this project. At reported average prices, this funding, sales costs and royalties can be recovered from a sale of 1700 carats of cut and polished stones equivalent to 2125 grams of rough germ quality of Ruby; at 25% recovery when cut for first alternative. For alternative two, this will be 800 carats of cut and polished stones equivalent to 1600 grams of rough gem quality Ruby before cut. It is known that single potatoes or nodules contain up to 1 kg of germ quality Ruby. At the rate of operatives planned for the Naberera mine, we expect that at least one big nodule will be intercepted per annum producing at least 1 kg of gem quality Ruby.

6.0 FINANCIAL PROJECTIONS.

 

6.1 Plant & Mining Equipment (Including essential spares)

ITEM	QUANTITY	UNIT PRICE	TOTAL
Excavator	1	200,000.00	200,000.00
Electric generator 60 KVA	1	33,000.00	33,000.00
Diesel draw compressor 600cfm	1	45,000.00	45,000.00
Electric Hoist 5 tons	1	28,000.00	28,000.00
4 x 4 double cabin pickup	1	16,000.00	16,000.00
Hand Held Drills	4	2,000.00	16,000.00
Rock Breakers	2	1,500.00	3,000.00
Workshop tools			2,000.00
Mechanical Sieve and Jiggers	2	2,500.00	5,000.00
Electric fans with duct	4	3,000.00	12,000.00
Total		331,000	360,000.00

6.2 Camping and construction.

ITEM	QUANTITY	UNIT COST	TOTAL COST
Furnished House for General Manager	1	16,000.00	16,000.00
Furnished House for senior staff	2	16,000.00	32,000.00
Furnished rooms for workmen with a room shared by four men	10	14,000.00	140,000.00
Shop	1	12,000.00	12,000.00
Water and sewerage	1	5,000.00	5,000.00
fencing	1	5,000.00	5,000.00
Security equipment (CCTV etc.)	1	3,000.00	3,000.00

6.3 OPERATING COSTS IN USD$

ITEM	Year 1	Year 2	Year 3	Year 4	Year 5
FUEL AND MAITENANCE	47,000.00	74,000.00	74,000.00	75,000.00	76,000.00
TIMBER	1,000.00	1,500.00	1,000.00	1,100.00	1,100.00
PIPING	500.00	1,400.00	500.00	500.00	500.00
STORES AND SERVICES	2,000.00	1,500.00	1,500.00	1,000.00	1,000.00
SALARIES AND WAGES	160,000.00	176,000.00	193,000.00	200,000.00	210,000.00
EXPLOSIVES	19,700.00	38,500.00	38,800.00	39,000.00	39,000.00
TOTAL	230,200.00	292,900.00	308,800.00	316,600.00	327,600.00
CONTIGENCY 10%	23,020.00	29,290.00	30,880.00	31,660.00	32,760.00
GRAND TOTAL	253,220.00	322,190.00	339,680.00	348,260.00	360,360.00

 

6.4 ESTIMATED REVENUE FROM ONLY RUBY SALES.

Estimates based on following assumptions.

• Average grade being 2 grams of quality Ruby per ton of ore.
• Average recovery from cutting and polishing gemstone being 25%. Thus 1 gram producing 1.25 carats of polished stones.
• 8 tons of ore mined from exploration operations per day.
• Price of USD$ 5000 to USD$ 10,000 per carat of polished Ruby. An average price of USD$ 5000 per gram used.

Year	1	2	3	4	5
Carats produced	200	400	600	800	1000
Revenue USD$	1,000,000.00	2,000,000.00	3,000,000.00	4,000,000.00	5,000,000.00

 

6.5 SUMMARY OF CAPITAL COSTS REQUIREMENTS AND PROPOSED FINANCING ARRANGEMENT IN USD$

 

Capital costs:

 

Plant and Equipment                       384,000.00

Camp and Construction                   213,000.00

Working Capital                              253,220.00

850,000.00