DEPLOYMENT OF REEF BALLS

 

 

 

Client:              PT Newmont Minahasa Raya

Project:            Habitat Enhancement Program – Buyat Bay and Adjacent Areas

Date:                July 1999

 

Prepared by:    Dave Lennon,

SINCLAIR KNIGHT MERZ

369 Ann St

BRISBANE   Q 4000

Australia

 

Ph:          +61 7-3244-7308

Fx:           +61 7 3244-7307

Email:    dlennon@skm.com.au

 

 

 

Introduction

 

The following is a brief report outlining a recommended strategy for the construction, deployment and monitoring of Reef Balls (specifically Pallet Balls and Bay Balls), in the Buyat Bay and surrounding area.  This strategy is designed to provide maximum success, safety and benefits from the habitat enhancement program.  However, it is important to note that there will need to be a degree of flexibility in the program, and a regular review of all activities should be conducted to allow ‘fine tuning’ of the program throughout its progress, and as data becomes available.  For example, it is not possible to predict exactly the growth and species composition that will be attracted in each area, therefore as observations are made they can be used to guide future deployment configurations. 

 

Additionally, there must be a regular review for quality control purposes to ensure the modules are being made to Reef Ball specifications.  This is absolutely essential and a condition of all purchasers and users of the moulds.  Quality control is important for many reasons, and includes safety of personnel involved as well as the environment. 

 

A habitat enhancement program such as this incorporates a philosophy of respect for the marine environment and efforts to work with it as well as understand it.  It is not to be promoted as a means to continue unsustainable exploitation of the sea by methods such as explosives, cyanide or overfishing.  This can not be emphasised enough, and every effort should be made to prevent (or at least discourage) unsustainable fishing, and fishing in general on the Reef Ball reefs should be discouraged for 6-12 months. 

 

 

Topics covered include:

 

-          Construction issues: materials, concrete mix, methodology, supervision, spare parts;

-          Deployment: potential objectives, selection of sites, future deployments, configurations, methods of deployment, and additional sites; and

-          Monitoring: suggested monitoring objectives and timing.

-          Appendices – checklist and responsible reef creation

 

 

 

Construction of Modules

 

There are three key aspects to construction – materials, methodology and supervision.

 

Materials

Materials used must comply with the specifications listed in the Reef Ball manual and most importantly, must not contain any of the materials listed as being not allowed. 

 

The following are NOT ALLOWED in the concrete mix:

 

q       Fly ash;

q       Sand that may be contaminated, contain salt or organic matter (ie river sand or beach sand that has not been screened and washed);

q       Accelerators, except for Calcium Chloride;

q       Silicone sprays - they may damage the balls and prevent colonisation by fouling organisms;

q       Admixtures that contain toxins or biologically active elements (including iron and nitrogen/phosphates – check with manufacturer);

q       Rebar, except for fiberglass rebar;

q       Form oil or release agents/waxes on the inside of the moulds, or anywhere else that may cause them to come into contact with the concrete (sugar water is okay to use); and

q       Any other products that contain plastics or petroleum products (Phil - make sure you get your toys out!).

 

Remember, your aim is to promote better respect for the ocean and create balanced reef ecosystems, therefore Reef Balls must be as environmentally friendly as possible.

 

Several of the required materials or admixtures are made by different manufacturers and consequently are sold under a variety of brand names.  The main ones are:

 

Silica Fume – this may be referred to as silica flour, Micropoz (Australia), microsilica, or WR Grace’s Force 10,000.  The brand currently being used from Aust/NZ (?) should be fine.  Stick to a reputable brandname and supplier. 

 

Super Plasticiser and Air entrainment mix – several brands available and the following brought from Australia are ok. 

- ‘Brickies Own Concentrated Mortar Plasticiser’ (Clear), by MELCANN

- ‘Clear Bycol’ – clear air entraining admixture for smooth working of concrete, by AJAX chemicals.

 

NOTE: Due to the fact that Newmont has regular shipments from the US, it may be worth ordering admixtures and even silica from the Reef Ball recommended supplier WR Grace – see manual for contact details and ask if they can ship concentrated formula that you simply add water to.  This would save on weight and shipping costs. 

 

Concrete Mix

1 cement, 1 sand, 1 gravel    Plus silica and admixtures.

 

Bay Ball = 3-5 kg of silica

Pallet Ball = 8-10 kg of silica

 

Admixtures – as per manufacturers instructions.

 

The crucial points to remember are:

-          Add at least half the required water first and then the silica.  This allows it to mix well before the cement etc is added.  The silica will only work if it is mixed thoroughly with the cement!  

-          Allow the concrete to mix for 10mins before pouring for the same reason as above (concrete testing labs in Australia run the mixer for 30mins before testing silica mixes).

-          Too much water weakens the mix, but too little can cause voids to form, especially in the Pallet Ball.  Technically the mix should have a 20cm slump, however it is easy to develop a visual gauge of the correct mix, and Harapan and Jumadi are now proficient at gauging by eye.  Basically the mix should ‘slide’ down itself in the mixer rather than ‘pour’ or ‘tumble’ in lumps.

 

 

The photo below is roughly how the mix should look.  It doesn’t show it too well, but the mix should not be runnier than this.

 

 

 

 

Methodology

 

The following describes the main points to remember and new techniques not covered during training due to short time frame.  The checklists cover a step-by-step account of methodology.  There isn’t anything too complicated about it, but attention to the small things pays off.  There is tremendous benefit from following a set ‘system’.  Time is saved, mistakes eliminated (or at least reduced!), and the modules are produced within specs. 

 

Harapan is very proficient, as you know, and has a good understanding of the methodology.  He should maintain a supervisory role until he thinks Jumadi (or someone else) is capable of taking over.  Harapan should then continue to check the operation regularly to ensure they continue to follow the system.  However, no system is perfect and if they find a way to do the job easier and faster, but still maintain required specs for mix, curing and handling, then let them go for it.

 

Two checklists have been produced in English and Indonesian and posted in the container.  The most useful is probably the one concerning starting and shutdown steps and are included in Appendix A.  At the end of pouring and cleaning equipment, it is important they remember to check supplies of sand, cement, silica, admixtures etc, and refill the admixture and sugar water bottles.  Doing so not only sets up the site for immediate start the next morning, but also prevents them from finding out the next day that they have run out of something that takes two days to arrive.  It will encourage them to keep an eye on supplies and to order in plenty of time.

 

Table 1 is an initial Reef Ball construction and deployment calendar that will help plan the program to tie in with barge arrivals and monitoring etc.

 

Key Points/Issues

 

q       Keep oils away from any areas that may cause them to come into contact with the concrete.

q       Make sure they are getting the gravel exposed and removing all the surface layer in order to ensure the pH is as low as it can be.

q       Keep reminding the crew to go easy on the plastic screw valves, they are already starting to strip the screw slot.  They must get the concrete out of the slot before attempting to unscrew it.  You have several spares and more can be ordered easily enough.

q       Keep the work area, moulds, balls and container clean.  Important to clean the moulds after each use otherwise the concrete will build up quickly forming a thick layer impossible to remove.  This makes it difficult for the mould to go together which adds stresses that may break the moulds, and makes repairs hard.

q       Keep modules damp under wrap for 3 days.

q       Keep track somehow the date each module was made.

q       Don’t make pointed ridges in the lobster holes as this can be a weak area that could crack on impact.  Make them with rounded tops.

q       Don’t put too much sand in bottom so that there is a crack or gap from the base into bottom holes.  This is a weak area and breakage could occur on impact.

q       With Pallet Balls it is a good idea to add enough cement to build up the ridge around the top.  This creates better strength for resistance to anchor strikes.

 

Variation of Modules

 

q       Vary the number of holes, ie balls added.  This is done for strength and also variety.  For stronger modules put less balls, especially in the upper area of the Bay Balls.  For example if anchor damage becomes a problem, make thicker walls by putting less air in the bladder and less balls in the upper area.  Also, variety is important for marine life, and some fish love caves, so less balls creates a good cave effect.  This will give you a more diverse reef.

 

q       Use leftover concrete to throw on modules, outside and inside.  The crew has done this, but lately we’ve let them use it to build a platform by the sea.  This creates even more lumps and bumps.  Caution: if you are going to do a floating deployment, don’t use a module with the concrete on the inside as it may puncture the bladder (assuming you use the bladder for floatation).  Also remember that this concrete won’t be as old as the module, so put it on modules from the day before so it is almost the same as age as module.

 

Supervision

 

I don’t need to emphasise the importance of good supervision.  Harapan is more than capable but will obviously need to go back to attending to his normal workload.  Jumadi is the natural next best person to supervise, but Harapan still needs to check regularly, ie every day for another week, then several times a week, or as needed (knowing Harapan, he will make surprise visits no problem).  If they follow the checklists, everything will go a lot better. 

 

The key areas to check for are:

 

q       Top wall thickness of modules (BB = min 50mm, PB = min 150mm) – thicker if anchor damage becomes a problem.  Remember thicker is not a problem, but thinner is;

q       Correct mix ratios and quantity of silica added;

q       Sufficient mixing time, they could be tempted to skimp on this;

q       Good exposure of gravel, ie removal of uncured surface cement;

q       Correct curing technique and curing time;

q       Quality of materials;

q       Safety gear, especially safety glasses and decent boots.  I understand this is the responsibility of the contractor, but Harapan will need to chase them up on this; and

q       All tools still remaining and hung on board.

 

Spares

 

The manual provides a list of few spares and repair kits required.  The fibreglass panels are very durable but may wear thin after awhile.  They can be easily patched or reinforced with standard fibreglass cloth and gel resin. 

 

The balls will last a year or more and you have a spare of the bladders plus ample spare tether and A0 balls.  Because they are standard boat buoys, most marine supply houses will have them.  The tether balls will have to come from Reef Balls in the US, but they always give you ample extras, so I don’t see them being an issue for awhile, unless of course they disappear.

 

The pins won’t break and I don’t think they will go walk about.  The main spares required will be items such as spray bottles, hammers, and perhaps the plastic screw valve plugs for the bladders and A0 buoys (you already have quite a few spare plugs).

 

Hard to find spares – we had trouble locating a few things so I’ve left you with the ones that I brought.  They were: air nozzle adapter and hose for scuba regulator – ore testing lab has air nozzles that can be adapted, or Petrosea truck mechanics also use a suitable nozzle.  If you have trouble let me know and I can send from Australia.  Scale – simple hand held fishing scale for weighing silica – not unique and should be able to be replaced in Manado.

 

NOTE: I recommend that you remove the regulator and octopus from the reg used for inflating the bladders.  They are getting beaten up and don’t need to be attached.  Make sure the plugs are put back in the first stage.

 

Safe Keeping

I think it is best if spares are kept with Harapan.  This will keep better control of them and if they need them, it is easy for them to request them.  Before storing, make a quick inventory of what you have.

 

 

Table 1:

REEF BALL

CONSTRUCTION AND DEPLOYMENT CALENDAR

 

DATE

BB made

PB made

*BB ready

*PB ready

Deploy/Comments

 

 

 

 

 

 

24-7

2

-

-

-

 

25-7

2

1

-

-

 

26-7

2

1

-

-

 

27-7

2

1

-

-

 

28-7

2

1

-

-

 

29-7

2

1

-

-

 

30-7

2

1

3 deployed

-

Detailed site surveys/buoy sites/deploy Bay Ball markers

31-7

2

1

 

-

Barge arrives?

AUGUST

 

 

 

 

 

1-8

1

1

1

1

DAVE LEAVES/set up barge

2-8

1

1

3

2

 

3-8

1

1

5

3

 

4-8

1

1

7, six deployed

4, 3 deployed

Deploy 1 PB at each site, plus two Bay Balls

5-8

1

1

3

1

 

6-8

1

1

5

2

 

7-8

1

1

7

3

 

8-8

1

1

8

4

 

9-8

1

1

9

5

 

10-8

1

1

10

6

 

11-8

1

1

11

7

 

12-8

1

1

12

8

 

13-8