Rock Processing - Attachments.pdf

DEPARTMENT OF THE ARMY

U.S. ARMY CORPS OF ENGINEERS, SACRAMENTO DISTRICT

1325 J STREET

SACRAMENTO CA 95814-2922

CESPK-ED-GB 15 SEP 2021

MEMORANDUM FOR RECORD

SUBJECT: Mormon Island Auxiliary Dam (MIAD) Stone Stockpile

The large stone (riprap) stockpile is planned to be sorted, crushed, and processed for use as riprap and bedding material on various Folsom Dam Raise projects. The existing stockpile location is at the west end of Folsom Reservoir’s Mormon Island Auxiliary Dam (MIAD) near Dike 8. The stockpile has variable sizes of stone, with maximum up to 8 to 13 feet on length.

Based on reports and laboratory test results, the quality of on-site rock, quartz diorite, is very hard and suitable for the required material gradations and design requirements for use as riprap and bedding.

Testing and evaluation of stone included visual characteristics, petrographic examination, absorption, soundness, abrasion loss, and wetting and drying. Results of testing were evaluated in accordance with EM 1110-2-2302 Chapter 6, section 6-2 and Table 6-1, and section 6-6.

Laboratory testing of stone samples were performed between 2013 to 2014. Field visual inspections were performed by government engineer and geologists in July 2021.

Laboratory testing and petrographic examination were performed by commercial laboratories on stone samples from stone stockpile located at Dike 7.

Petrographic Examination

Results of petrographic examinations are summarized as follows:

Two Petrographic Examination were performed in accordance with ASTM C295. Based on petrographic examinations, stones at the stockpile are composed of igneous rocks, classified as either granodiorite or quartz diorite. All stone materials had satisfactory physical properties for use as riprap.

Physical Properties

The results of laboratory testing are summarized as follows:

Bulk specific gravity determined in accordance with ASTM C127: Apparent specific gravity varied from 2.33 to 2.75; bulk-saturated surface dry specific gravity values varied from 2.32 to 2.73.

Absorption determined in accordance with ASTM C127, reported results between 0.1to

0.5 percent.

Sodium soundness determined in accordance with ASTM C88, reported a loss of between 0.54 to 3.85 percent.

Abrasion Loss determined in accordance with C535: Abrasion testing reported a loss of between 16.83 to 31.17 percent.

Wetting/Drying Durability Testing

Wetting and drying test was performed in accordance with CRD-C 169 Standard test method for resistance of rock to wetting and drying. Eight representative stone samples were collected from the stockpile prepared and tested in accordance with COE CRD-C- 169 in 2012 and 2014. Representative stone samples were collected from the Dike 7 stockpile and laboratory testing reported 0 to 0.3 percent mass loss. No changes in the stone were observed after 30 cycles of wetting and drying. Stone materials exhibit negligible loss and were essentially unaffected by the test.

Criteria

EM 1110-2-2302 specifies the criteria for stone materials. EM 1110-2-2302 paragraph 4- 3 advises that preliminary approximations of stone quality specified in Table 4-1 indicates that granite and Quartzite are expected to provide good durability.

Laboratory testing was performed by commercial laboratories on stone samples in accordance with EM 1110-2-2302, paragraphs 6-1 and 6-2. Table 6-1 provides recommendations and general criteria for evaluating stone. Recommended testing includes performing petrographic examination, laboratory testing for durability and physical properties, field visual inspections and field testing. All the testing recommendations listed in Table 6-1 were evaluated with exception of Freezing-Thawing.

Petrographic examination did not report presence of swelling clay mineral, no expansion, fracturing, flacking, cracking, or degradation. The rock was also sampled, prepared, and tested in accordance with CRD-C-149 “Method of Testing for Expansive Breakdown on soaking in Ethylene Glycol. Swelling was not detected on all samples. All physical testing were in compliance with EM 1110-2-2302, Table 6-1.

Conclusion

The granite/quartz diorite should be considered durable and suitable for use as riprap, stone protection materials, and other large stone applications.

Fiorella J. Fuentes, P.E.

Material Engineer

U.S. Army Corps of Engineers Sacramento District

Testing was performed on the on-site rock. A summary of testing is as follows:

Test Name Test Result Project Specification

EM-1110-2-2302

Specification

Petrographic Examination No swelling clays No swelling clays No swelling clays

Absorption 0.50% <2% <2% Abrasion Loss 23% (1000 rev) Maximum loss

40% 20-40% (500 rev)

Wetting and Drying

<0.1% loss, no observed cracking

Maximum loss 1%, no major cracking Local experience

Bulk Specific Gravity 2.717 2.6 minimum Local experience

Ethylene Glycol

No expansion, swelling, flaking, cracking, or degradation observed

No expansion, swelling, flaking, cracking, or degradation observed

No expansion, swelling, flaking, cracking, or degradation observed Magnesium Sulfate Soundness

2.5% loss Maximum loss 5%

Maximum loss 10%

Additional information regarding the test results can be found in Appendix 22 of the Folsom Dam Auxiliary Spillway Foundation Report.

Based on the above summarized results, the material is suitable for additional processing as riprap. Any material not meeting project specifications for riprap will be processed further for use as bedding. Additional quality control and quality assurance observation and testing will be required during processing to ensure material meets project specifications.