Armstrong Grease Tables

Plate 1

Plate 11

Plate 111

Models

Mark II
This unit consists of a grease screen divided into 2 or 3 channels depending on the gravel fractions treated and the double or triple overlying screen employed. The screen has an overlying scrubber and a feeder bin. Underlying the grease screen screen is a water tank, a water heating system and a sand filter to keep the spray water clean and at the correct operating temperature of 20 to 24 degrees C. An electrical box housing the electrical operating system is supplied with the unit. All parts to be galvanized and painted and all fittings to be of stainless steel. An electrical box housing the electrical operating system is supplied with the unit.

The grease screen consists of a stainless steel screen pulled drum tight between a heavy duty rectangular tubing frame with underlying square tubing supports. The diamond grease is applied with a spatula in two strips from the underneath the screen and protrudes 1 to 2mm above the screen. This system allows for minimal grease removal when removing diamonds or when renewing the grease. Simply scrape the grease off the top of the screen and force a new layer up from underneath the screen.

See Plate 1

Mark III This unit is the same as for the Mark II but incorporates a built in triple deck vibratory screen to classify the gravel into three different size fractions after scrubbing. These fractions are fed similtaneously over the grease screen which is split lengthwise to accommodate the three separate size fractions.

Each of the above units are designed to be transported on the back of a SUV. The operative capacity of these units is 0.3 to 0.6 tons of concentrate per hour.

See Plate II

Mark IV This is a larger capacity unit which can handle up to 3 tons of concentrate per hour. It is equipped with a 4 deck vibratory screen to supply 4 separate size fractions to the grease screen which is split into 4 channels. It is equipped with a larger scrubber than the Mark II and Mark III units but has all the facilities of these units.

See Plate 111 excluding the scrubber

All units are assembled with plated high tensile bolts and nuts and all components are powdercoated to the customer's colour requirements.

Any of the units can be fitted into an insulated, airconditioned 20ft shipping container with landing legs if required at an extra cost.

Completely enclosed pipe conveyors can be supplied at an extra cost as follows:

6 metre  200mm φ    1.50kw

6 metre  150mm φ    0.75kw

12 metre 200mm φ   1.50kw

12 metre 200mm φ   0.75kw

Kw power requirements are minimal for the various units and are as follows:

Mark I   4.90kw

Mark III 5.08kw

Mark IV 7.64kw

All units are supplied ex works.

An optional extra is to have the equipment built into a shipping container.

Conditions of payment are 50% deposit on placement of order and 50% on collection from our factory premises.

Packaging, transport, field installation and commissioning is for the customer's account unless otherwise arranged.

Factory training can be provided if required.

DIAMOND RECOVERY CRITERIA

For efficient diamond recovery over grease the following factors are essential:

1. The feed concentrate must be scrubbed efficiently to remove any coating on the diamond which may cause it to become non hydrophobic (this coating may be discernibly molecular or atomic by degree).
2. The concentrate must be efficiently screened into size ranges namely 1-2mm, 2-4mm, 4-8mm, 8-16mm and 16-32mm and passed over the grease in individual size ranges. Non compliance will result in larger non diamond wettable material dislodging smaller non wettable (hydrophobic) diamonds after they have stuck to the grease.
3. Screening and scrubbing of the feed concentrate should take place immediately prior to the feed concentrate being passed over the grease table. Retaining the above material in holding bins for any length of time prior to the grease recovery can result in the build up of coatings on the diamonds (at a molecular or atomic level) which could jeopardise the hydrophobic nature of the diamonds.
4. The scrubbed water must be removed after scrubbing and the concentrate washed with clean water before being passed over the grease table.
5. The water used on the grease table must be kept clean and of good quality otherwise minute particle build up on the grease surface may cause the grease to become ineffective. An efficient filtration system can be employed where water scarcity is a problem.
6. The grease table processing water must be kept at an operational temperature of between 20-24°C. At temperature below 18°C definite diamond loss will occur. At temperatures above 26°C gunge material will start sticking to the grease.
7. The material feed must be kept wet at all times as any dry material will immediately stick to the grease and clog the grease screen.

As you can see from the Gondwanaland Diamonds website we at present manufacture 3 different models.

Mark I
Here criteria 5, 6 and 7 are met for efficient grease diamond recovery.

Mark II
Here criteria 1, 5, 6 and 7 are met for efficient grease diamond recovery.

Mark III
Here all criteria 1 to 7 are met for efficient grease diamond recovery.

Mark IV
This is a larger capacity version of model Mark III.

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Optional extras

1. A transparent removable glove box is built in between the multi deck screen and the grease table to make the diamond recovery operation more secure.
2. A camera is mounted inside the glove box for remote monitoring of the diamond recovery operation.
3. A grease recovery and diamond cleaning system operating within the glove box.
4. Suitable pipe conveyors for feeding and extracting material from the grease recovery units.

The prices of the above are dependent on customer requirements and are available on request.

The model most suitable will depend on your customer's facilities to efficiently feed the machine, to screen the material into the required sizes for treatment, etc as set out in requirement 1 to 7 for efficient grease recovery.
Whatever facilities your customer has in place will determine the model most suitable. If your customer has none of these, our recommendation would be model Mark III together with any optional extras he may choose.