Proctor/Fagerberg Test

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Proctor/Fagerberg Test Apparatus.

The Proctor/Fagerberg Test (PFT), sometimes abbreviated as PFC70 or C70, is one of the three test methods stated in Appendix 2 of the International Maritime Solid Bulk Cargoes Code (IMSBC Code) used to determine the Transportable Moisture Limit (TML) of Group A or liquefiable solid bulk cargoes. The two other test methods stated in Appendix 2 of the IMSBC Code used to determine the TML of Group A or liquefiable solid bulk cargoes are the Penetration Test (PT) and Flow Table Test (FTT)[1].

There are two modified versions of this test method known as the Modified Proctor/Fagerberg Test for Iron Ore Fines[2] and Modified Proctor/Fagerberg Test for Coal[3].

See: Modified Proctor/Fagerberg Test (MPFT)

Note: All information contained within these boxes were obtained from Appendix 2 of the International Maritime Solid Bulk Cargoes Code, 2013 Edition[1].


Note: All information contained within these boxes are collaborative notes and not specifically recommended in the International Maritime Solid Bulk Cargoes Code, 2013 Edition[1]


Note: Please refer to the latest edition of the International Maritime Solid Bulk Cargoes Code (IMSBC Code) before performing the test described below.


History[edit]

A timeline of events relating to TML Testing. This includes the Penetration Test, Flow Table Test, Proctor/Fagerberg Test and Modified Proctor/Fagerberg Test for iron ore fines. Also included are the International Maritime Solid Bulk Cargoes Code (IMSBC Code) editions[4].

The Proctor/Fagerberg test was first published in Stockholm in 1962 by Bengt Fagerberg and Kjell Eriksson[5] as part of a committee established by the Swedish Mining Association and several Scandinavian mining companies. The committee was given the task to develop a simple method for determining the critical moisture content (CMC) of individual cargoes [6]. The test method is based upon use of the Proctor apparatus developed in soil mechanics [7] and was adopted by the International Maritime Organization, for use in the IMSBC Code, between 1991 and 1998 [8][9].

In 2013 and 2014 the Proctor/Fagerberg Test was modified for use with Iron Ore Fines (IOF)[2] and Coal[3], respectively.

See: Modified Proctor/Fagerberg Test (MPFT), Modified Proctor/Fagerberg Test for Iron Ore Fines and Modified Proctor/Fagerberg Test for Coal.

Timeline[edit]

Year Document Development Reference(s)
1962 Fuktighetens Inflytande pa Sligtransporter Till Sjoss Published [5][6][10]
1965 Hazards of Shipping Granular Ore Concentrates (Part 1 and 2) Published [11][8]
1971 Determination of Critical Moisture Contents in Ore Concentrates Carried in Cargo Vessels Published [6][10]
1991 to 1998 Code of Safe Practice for Solid Bulk Cargoes (BC Code) Introduced [1][8]
2013 Modified Proctor/Fagerberg Test for Iron Ore Fines Introduced [2]
2014 Modified Proctor/Fagerberg Test for Coal Introduced [3]

Scope[edit]

  1. Test method for both fine and relatively coarse-grained ore concentrates or similar materials up to a top size of 5 mm. This method should not be used for coal or other porous materials.
  2. Before the Proctor/Fagerberg test is applied to coarser materials with a top size greater than 5 mm, an extensive investigation for adoption and improvement is required.
  3. The transportable moisture limit (TML) of a cargo is taken as equal to the critical moisture content at 70% degree of saturation according to the Proctor/Fagerberg method test.

Apparatus[edit]

Proctor/Fagerberg Apparatus (figure 1.3.2 in Appendix 2 of the IMSBC Code, 2013 Edition)
  1. The Proctor apparatus (see figure 1.3.2) consists of a cylindrical iron mould with a removable extension piece (the compaction cylinder) and a compaction tool guided by a pipe open at its lower end (the compaction hammer).
  2. Scales and weights and suitable sample containers (See section 3.2 of Appendix 2 of the IMSBC Code).
  3. A drying oven with a controlled temperature interval from 100oC to maximum 105oC. This oven should be without air circulation.
  4. A suitable mixer. Care should be taken to ensure that the use of the mixer does not reduce the particle size or consistency of the test material.
  5. Equipment to determine the density of the solid material, for example a pycnometer.

Temperature and Humidity[edit]

It is preferable to work in a room where the samples will be protected from excessive temperatures, air currents and humidity variations. All phases of the material preparation and testing procedure should be accomplished in a reasonable space of time to minimize moisture losses and, in any event, within the day of commencement. Where possible, sample containers should be covered with plastic film or other suitable cover.


Procedure[edit]

Establishment of a Complete Compaction Curve[edit]

A representative sample according to a relevant standard (see section 4.7, page 20 of the IMSBC Code) of the test material is dried at a temperature of approximately 100oC. The total quantity of the test material should be at least three times as big as required for the complete test sequence. Compaction tests are executed for five to ten different moisture contents (five to ten separate tests). The samples are adjusted in order that dry to almost saturated (plastic) samples are obtained. The required quantity per compaction test is about 2000 cm3.


It is noted that according to similar procedures it is stated that oven drying a soil can damage fine particles within a sample and reduce the ability for the sample to retake water and therefore produce unreliable results. It is recommended to air dry the sample if it requires drying.

The Modified Proctor/Fagerberg Test for Iron Ore Fines states:

A representative sample according to a relevant standard (see section 4.7, page 20 of the IMSBC Code) of the test material is dried at a temperature of approximately 60oC or less to reduce the samples moisture to suitable starting moisture, if needed. The representative sample for this test should not be fully dried, except in case of moisture content measurement[2].


At each compaction test a suitable amount of water is added to the sample of the dried test material and mixed thoroughly for 5 minutes. Approximately one fifth of the mixed sample is filled into the mould and leveled and then the increment is tamped uniformly over the surface of the increment. Tamping is executed by dropping the hammer 25 times through the guide pipe, 0.2 m each time. The performance is repeated for all five layers. When the last layer has been tamped the extension piece is removed and the sample is leveled off along the brim of the mould. When the weight of the cylinder with the tamped sample has been determined, the cylinder is emptied, the sample is dried and the weight is determined.

The test then is repeated for the other samples with different moisture contents.


It is noted:

  1. It is necessary to control the total amount of soil compacted since, if the amount of soil struck off after removing the collar is too great, the test results will be inaccurate as the energy input will not be within the required tolerances. Some large particles may protrude a little more than 5 mm above the surface for the passing 37.5 mm material. Suitable allowances in the trimming process must be made for these particles but the average height of the compacted sample before trimming should not exceed 5 mm above the mould[12].
  2. While trimming the surface of the sample, the procedure may depend on the characteristics of the soil[12]:
    1. Essentially fine-grained soil - Trim the compacted soil level with the top of the mould by means of the straightedge; use smaller size material to patch any holes developed in the surface from removal of coarse material during trimming.
    2. Soil containing stones - Trim the compacted soil in the mould ensuring that portions of stones standing above the top of the mould are compensated by hollows of about the same volume below the top of the mould.
  3. It is not recommended to reuse material that has been placed in the oven for the determination of moisture content. When the sample is placed into the oven the heat damages the particles, reduces the ability for the material to retake water and will reduce the accuracy of the results if reused.

Definitions and Data for Calculations[edit]

empty cylinder, mass in grams: A

cylinder with tamped sample, mass in grams: B

wet sample, mass in grams: C

C = B -– A

dry sample, mass in grams: D

water, mass in grams (equivalent to volume in cm3): E

E = C –- D

Volume of cylinder: 1000 cm3


It is noted to use the exact volume of the mould that has been measured directly using a vernier caliper. Using 1000 cm3, as stated above, might lead to inaccurate results if the volume of the mould is not exactly 1000 cm3, which they rarely are.


Calculation of Main Characteristics[edit]

density of solid material, g/cm3 (t/m3): d

dry bulk density, g/cm3 (t/m3): γ

γ = D / 1000

net water content, volume %: ev

ev = E / D x 100 x d

void ratio: e (volume of voids divided by volume of solids)

e = ((1000 - D) / D) = d / γ = - 1

degree of saturation, percentage by volume: S

S = ev / e

gross water content, percentage by mass: W1

W1 = E / C x 100

net water content, percentage by mass: W

W = E / D x 100

It is noted that there is a typo in the text above. The line that reads:

e = ((1000 - D) / D) = d / γ = - 1

should read:

e = ((1000 - D) / D) = d / γ - 1

It is also noted that by using the above equations the operator must remove the entire sample from the mould to determine the bulk density (i.e. γ = D / 1000). This is not recommended as there will always be residue from the sample left within the mould.

The below equations may assist, along with the above, in calculating the main characteristics:

Note that this method involves first calculating the net water content by weight and then converting to the gross water content by weight, which is what the Transportable Moisture Limit (TML) is reported in.

The following equation is used to determine the bulk density of the sample:

Pftbulkdensity.gif

Where:

m1 = is mass of mould and base plate (in g),
m2 = is mass of mould, base plate and compacted sample (in g),
ρb = is the bulk density of each compacted specimen (in t/m3) and
V = is internal volume of the mould (in cm3).

The following equation is used to determine the net water content by weight:

Eqn (4).png

Where:

w = net water content by weight (%),
m3 = is mass of container and wet sample (in g),
m4 = is mass of container and dry sample (in g),
m5 = is mass of container (in g),
Ww = mass of water and
Ws = mass of solids.

The following equation is used to determine the dry density of the sample:

Pftdrydensitynew.png

Where:

w = net water content by weight of each compacted specimen (%),
ρb = is the bulk density of each compacted specimen (in t/m3) and
ρd = is the dry density of each compacted specimen (in t/m3).

The following equation is used to determine the void ratio of the sample:

Pftvoidratio.gif

Where:

e= void ratio of each compacted specimen,
ρst = is the specific gravity of the sample (in t/m3) and
ρd = is the dry density of each compacted specimen (in t/m3).

To convert the net water content by weight to the gross water content by weight the following equation can be used:

Gwctonwcwithw.png

Where:

w1 = gross water content by weight (%) and
w = net water content by weight (%).

You can also use the converter provided on the main site by clicking the following link:

http://tmltesting.com/calc-moisturecontent.php

The following equation is used to determine the void ratio at different gross water contents for corresponding degrees of saturation:

Voidratiocalculationwithgwc.png

Where:

e = void ratio,
w1 = gross water content by weight (%),
ρst = is the specific gravity of the sample (in t/m3) and
S = degree of saturation (%).

You can also use the calculators provided on the main site by clicking the following link:

http://tmltesting.com/other.php


Presentation of the Compaction Tests[edit]

Graphical representation of the compaction curve produced during the Proctor/Fagerberg Test (figure 1.3.4.5 in Appendix 2 of the IMSBC Code, 2013 Edition)
Graphical representation of a compaction curve produced by performing a Proctor/Fagerberg Test (PFT) on a solid bulk cargo. Source: http://TMLTesting.com

For each compaction test the calculated void ratio (e) value is plotted as the ordinate in a diagram with net water content (ev) and degree of saturation (S) as the respective abscissa parameters.


It is noted that since the Transportable Moisture Limit is determined in the gross water content by weight, similar to the Penetration Test and Flow Table Test, the void ratio should be plotted against the gross water content by weight.


Compaction Curve[edit]

The test sequence results in a specific compaction curve (see figure 1.3.4.5).

The critical moisture content is indicated by the intersection of the compaction curve and the line S = 70% degree of saturation. The transportable moisture limit (TML) is the critical moisture content.


Typical Values[edit]

Below are some typical Transportable Moisture Limit (TML) values, determined using the Proctor/Fagerberg Test, for common solid bulk cargoes:

Material Typical TML values determined using the Proctor/Fagerberg Test (% GWC)
Iron Ore Fines 8.00 - 16.80 (Average = 11.03)[9]

Discussion[edit]

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References[edit]

  1. 1.0 1.1 1.2 1.3 International Maritime Organisation, International Maritime Solid Bulk Cargoes Code, 2013 Edition, London: International Maritime Organization.
  2. 2.0 2.1 2.2 2.3 International Maritime Organisation, DSC.1/Circ.71 - Early Implementation of Draft Amendments to the IMSBC Code Related to the Carriage and Testing of Iron Ore Fines, 15 November 2013, London. (Download PDF)
  3. 3.0 3.1 3.2 Modified Proctor/Fagerberg Method for Coal, 24 November 2014. (Download PDF)
  4. Munro, M., & Mohajerani, A. (2016). Moisture Content Limits of Iron Ore Fines to Prevent Liquefaction During Transport: Review and Experimental Study. International Journal of Mineral Processing, 148. doi: http://dx.doi.org/10.1016/j.minpro.2016.01.019
  5. 5.0 5.1 Fagerberg, B., Eriksson K., Fuktighetens Inflytande pa Sligtransporter Till Sjoss, 1962. (Download PDF)
  6. 6.0 6.1 6.2 Fagerberg, B., Determination of Critical Moisture Contents in Ore Concentrates Carried in Cargo Vessels. Minerals Transportation, 1971: p. 174-191. (Download PDF)
  7. American Society for Testing and Materials, ASTM Designation D698 - Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort. 2012.
  8. 8.0 8.1 8.2 Munro, M. and A. Mohajerani, Moisture Content Limits of Iron Ore Fines to Prevent Liquefaction During Transportation. International Journal of Mineral Processing.
  9. 9.0 9.1 Munro, M. and A. Mohajerani, Determination of Transportable Moisture Limit of Iron Ore Fines for the Prevention of Liquefaction in Bulk Carriers. Marine Structures, 2015. 40(1): p. 193-224.
  10. 10.0 10.1 Munro, M. and A. Mohajerani, Determination of Transportable Moisture Limit of Iron Ore Fines for the Prevention of Liquefaction in Bulk Carriers. Marine Structures, 2015. 40(1): p. 193-224.
  11. Fagerberg, B., Hazards of Shipping Granular Ore Concentrates (Part 1 and 2), Canadian Mining Journal, vol.856, pp. 53-57,81-86.
  12. 12.0 12.1 Standards Australia, AS 1289.5.1.1-2003 - Soil compaction and density tests - Determination of the dry density/moisture content relation of a soil using standard compactive effort. 2003.

See Also[edit]

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