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De Bruin, N. J. H., J. Grobler, and C. A. Pollard, 1991. The SCEM 66 Water Control System. Institute of Shaft Drilling Technology Annual Technical Conference, April 24-26, 1991, Las Vegas, Nevada.

THE SCEM 66 WATER CONTROL SYSTEM
BY
NJH DE BRUIN – PASMINCO MINING, AUSTRALIA
J GROBLER – INVENTOR SCEM 66, SOUTH AFRICA
DR CA POLLARD – CEMENTATION MINING LTD, UNITED KINGDOM

Introduction
The uncontrolled flow or leaking of water into underground excavation or through dam walls, foundations and the like, can be one of the most annoying and difficult problems faced by engineers and operators. Once aquifers have been exposed by excavation it is generally impossible to effectively control or seal water flows through the use of conventional grouting methods and materials.

The SCEM 66 water control system offers a solution to most of these problems.

Grouting Materials
Grouting may be defined as the injection of fluids, with or without fillers, into a matrix such as concrete, rock or soil to fill the voids. Grouting materials may be broadly classified according to the size of the contained solids as indicated in Table I....Read More

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Martin, R. W., M. G. Gardner, B. W. Bowan, II, D. Van Dyk, N. J. Grobler, M. Jimba, and H. Masaki, 2017. Water Sealing with NOH2O^® on the Fukushima Site -17477. WM2017 Conference, March 5-9, 2017, Phoenix, Arizona.

Richard W. Martin¹, Martin G. Gardner¹ and Bradley W. Bowan II¹
Deon Van Dyk², Nico J. Grobler²
Masaki Jimba³
Hiroshi Masaki^4,5
¹Atkins Energy Federal EPC, Inc., Columbia, MD 21046
²Sovereign Hydroseal Pty. Ltd, Bibra Lake, Western Australia 6163
³IHI Corporation, Yokohama, Japan 235-8501
⁴International Research Institute for Nuclear Decommissioning, Tokyo, Japan
⁵Toshiba Corporation, Yokohama, Kanagawa, Japan

ABSTRACT
The Fukushima Daiichi nuclear site is still recovering from the natural disaster of March 11, 2011. Much of the recent recovery work has been focused on mitigating ground water intrusion into the radioactively contaminated basements of the reactor and turbine buildings of units 1 – 4. Other recovery efforts involve potentially sealing the vent lines in the primary containment vessels of units 1 - 3 to maintain a flooded vessel for core cooling and shielding. This paper details preliminary test results of a proprietary grout – NOH2O™ – in sealing/plugging those vent lines to allow flooding of the primary containment vessel. Several partial and full-scale tests were conducted on primary containment vessel vent line mockups between March and October 2015 to ascertain the effectiveness of NOH2O^® in sealing vent lines that have flowing water, which is problematic for conventional cement-based grouts that require relatively protracted set times. In contrast, NOH2O^® can be used with a proprietary accelerant to provide instant set. The other key advantage of NOH2O^® is its ability to penetrate even the smallest of cracks and porous soils, following and moving with the water flow and creating a continuous, impermeable barrier. It is also extremely flexible once set, conforming to its enclosure as upstream water head increases. Finally, the material’s extremely high radiation resistance and longevity make it an ideal candidate for a permanent solution in high rad environments....Read More

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Gancarz, P., J. Minturn, N. Grobler, and D. Van Dyk. 2017. Leak Mitigation Grouting for New York Subway Tunnels. Society for Mining, Metallurgy & Exploration, Rapid Excavation and Tunneling Conference, June 4-7, 2017, San Diego, California.

Paul M. Gancarz ■ Sovereign-Thyssen L.P.
John E. Minturn ■ Sovereign-Thyssen L.P.
Nico J. Grobler ■ Sovereign-Thyssen L.P.
Deon Van Dyk ■ Sovereign-Thyssen L.P.

ABSTRACT
Groundwater intrusion into tunnels is a severe challenge encountered by contractors and owners. Significant cost over the tunnel’s lifetime illustrates the pivotal role of dewatering and leak mitigation. Polymer-based emulsion grouts have provided permanent cutoff barriers in dams, mines and tunnels for over forty years. Our study addresses the failure of membrane waterproofing systems in mitigating groundwater infiltration, illustrates the technology, performance and material characteristics of polymer emulsions, and how its application to water cutoff grouting compares with available cementitious and resinous systems. Case histories into the use of polymer emulsions for tunnel rehabilitation in New York will be provided.

INTRODUCTION
Preliminary Investigations
Given the tremendous burden tunnel leakage can pose during construction (both as a cost and a scheduling impediment), it is prudent to set up some form of leak monitoring once the tunnel’s concrete liner is placed and has had time to cure. This can be done by assigning one or several field inspectors to regularly walk the site searching for leaks – paying special attention to areas which permanently house sensitive equipment, behavior during cold seasons and after a significant rainfall event. In the event that unacceptable tunnel leakage is detected, a significant lead time is gained to address these leaks.
Once the determination is made to address any leaks, project background is valuable in treating them quickly and effectively. Understanding the hydrogeology of the surrounding ground medium – variations in the groundwater table, nearby bodies of water, geotechnical properties of the surrounding rock or soil – all play a role in how water infiltrates the structure. Equally important is the tunnel structure itself. Of particular interest is the initial waterproofing system and the nature of how it was installed, as tunnel leakage is the result of deficiencies to the waterproofing. Knowing concrete thickness, distribution of rebar, stress distributions (and therefore where there is likely to be a concentration of structural cracks) – all of this information is valuable, and can make a difference in the duration and effectiveness of a leak mitigation program.
Polymer-Based Emulsion Grout
Polymer-based emulsion (PBE) was developed in the early 1970s as a means of sealing water with high velocity washout rate as well as very high hydrostatic pressure, typically applied to deep shaft mines in South Africa. In its fluid state, PBE exhibits waterlike properties including a low viscosity, a specific gravity comparable to water and miscibility in water. The particle size of PBE is less than one micron, which allows PBE to permeate through very small cracks. Due to its waterlike properties PBE is capable of spreading out long distances, greatly reducing the required number of grout holes (Sovereign, 2011). Read More

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Gancarz, P., J. Minturn, N. Grobler, and D. Van Dyk. 2017. Polymer Emulsion Grouting for Water Cutoff in Tunnel Structures. American Society of Civil Engineers Geo-Institute, Grouting 2017: Grouting, Deep Mixing and Diaphragm Walls, July 9-12, 2017, Honolulu, Hawaii.
Paul M. Gancarz, P.E., M.ASCE,¹ John E. Minturn,²
Nico J. Grobler³, and Deon Van Dyk⁴

¹Lead Grouting Engineer – Northeast USA, Sovereign-Thyssen L.P., New York, NY USA;
email: pgancarz@sovereign-thyssen.com
²General Manager, Sovereign-Thyssen L.P., New York, NY USA;
email: jminturn@sovereign-thyssen.com
³Vice President, Sovereign International Inc., New York, NY USA;
email: ngrobler@sovereignhydro.com
⁴Lead Hydrologist, Sovereign International Inc., New York, NY USA;
email: dvd@sovhyd.com

ABSTRACT
Seepage in underground structures is a common problem facing contractors and facility owners alike. Unwanted groundwater intrusion – which arises as a consequence of initial construction – can develop into a costly repair and a prolonged tunnel maintenance program. The objective of this study is to illustrate the technology, performance and material characteristics of polymer emulsion and how it has been successfully applied to the problem of tunnel facility leakage. A regular grid of grout holes are drilled through the tunnel’s structural lining and polymer emulsion is pressure grouted into the annulus. The result is the formation of a dense, flexible barrier along the exterior of the underground structure which prevents water from entering the facility. Curtain grouting with polymer emulsion has been used in tunnel structures to provide a cost-effective solution for tunnel leakage with minimal impact to project schedules.

INTRODUCTION
Groundwater entry into facilities located near or below the groundwater table places significant burden on both contractors and owners. Pumping and treatment cost, protecting sensitive equipment, service delays and maintaining public spaces can be considerable. It is therefore important, given the significant impact on cost over the tunnel’s lifetime, that fully investigating, monitoring and preventing groundwater infiltration is done early in the construction cycle.
Leakage often occurs as the result of deficiencies in the initial waterproofing system. Initial waterproofing for underground structures typically consist of PVC or HDPE sheet membranes, which are installed in a grid-like fashion between the initial and final structural lining systems. Sheets are usually either welded together with a hot-air element, or bonded...Read More

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Goodman, W., D. Van Dyk, N. Grobler, and A. Osborne, 2019. Physical Properties of Polymer-Based Emulsion (PBE): A Unique, Flexible, Water-Sealing Grout for the Mining, Tunneling and Nuclear Industries. Finnish Tunneling Association Nordic Grouting 2019, Helsinki, Finland, September 2-3, 2019

ABSTRACT
Polymer-Based Emulsion (PBE) grout was developed in the 1970s and initially used to seal high pressure-high rate water inflows into deep subsurface South African mines. PBE use broadened over the decades to include water-sealing in mines in other countries and in underground tunnels for subway systems and other municipal infrastructure. Because of its radiation tolerance, PBE has been evaluated and used for water-sealing at nuclear facilities.

PBE is a suspension of colloidal polymer emulsoids dispersed in a solution of additives promoting flow and adhesion. PBE is injected in a fluid state and remains fluid until activated. PBE is a non-Newtonian, dilatant fluid; it sets by internal shear as the grout passes through fractures or other voids in water-bearing media. Set time may also be controlled chemically with the use of activator or inhibitor. Still, PBE is differentiated from solution grouts, because it is a single-part grout whose set does not require a chemical reaction.

After successful application in South Africa, PBE use for sealing mine leaks broadened geographically to the UK, Australia, Namibia, Zambia, USA, Canada and Russia. The grout has successfully sealed discrete inflows higher than 9800 liters per minute at pressures up to 17,000 kilopascals. PBE use broadened, because it is significantly less vulnerable to washout than commonly used cementitious grouts. Furthermore, unlike acrylamides and acrylates, PBE does not contain hazardous constituents in either liquid or solid form.

PBE has been successfully used to seal underground tunnel leaks in North America, Africa, Australia, Singapore and Hong Kong. Because of its low viscosity, small particle size and, hence, significant spread behind liner systems, PBE allows for drilling of fewer, more widely-spaced injection points than commonly used solution grouts, thereby decreasing drilling and labor costs for grouting programs. PBE bonds strongly to concrete and rock; it does not get pushed out of fractures in tunnel linings in response to recovering positive-side water pressure.

PBE has also been applied at a nuclear power facility in Canada, has been considered for use at Fukushima, Japan and is planned for use at a research facility in the United States. Laboratory testing has demonstrated that PBE is radiation-tolerant and can survive exposure levels up to 100 MRad without adverse changes to its physical properties and sealing capabilities. Based on studies for nuclear applications, PBE life has been estimated to be greater than 125 years.
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