WO2009097261A1

WO2009097261A1 - Resin grouts for anchor systems

Info

Publication number: WO2009097261A1
Application number: PCT/US2009/032099
Authority: WO
Inventors: Anthony John Spencer Spearing; Hendrik Gideon Johannes Pretorius
Original assignee: Jennmar Corporation
Priority date: 2008-01-28
Filing date: 2009-01-27
Publication date: 2009-08-06

Abstract

A grout system for use in connection with a reinforcing member, including a first portion comprising a polymerizable component, the polymerizable component comprising substantially only acrylic resin; and a second portion comprising an activator for polymerizing said acrylic resin upon mixing of said first and second portions.

Description

RESIN GROUTS FOR ANCHOR SYSTEMS

CROSS REFERENCE TO RELATED APPLICATIONS

(0001 J This application claims the benefit of United States Provisional Application No. 61/062,655, filed January 28, 2008, entitled "Resin Grouts For Anchor Systems"; United States Provisional Application No. 61/062,631, filed January 28, 2008, entitled "Resin Grout Systems For Use In Anchor Systems"; and United States Provisional Application No. 61/062,654, filed January 28, 2008, entitled "Foam Systems For Protection Of Anchor Systems", all incorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION Field of the Invention

[0002] The present invention relates to resin grouts for anchor systems and, particularly,, to resin grouts for use in stabilization of reinforcement members such as rock bolts or cable bolts (referred to herein collectively as either anchor bolts or reinforcement members) used in underground mining operations. Description of Related Art

[0003] Currently available resin grout for anchoring reinforcement members in underground mines is typically provided in elongated dual compartment cartridges containing: (1) a curable polyester resin composition; and (2) a catalyst (for example, benzoyl peroxide). The cartridge is generally produced from a thin, rapturable film. After bore holes are drilled for anchor bolts, the cartridges are inserted into the blind end of the bore hole. When an anchor bolt is inserted into the bore hole and rotated, the cartridge ruptures so that the two components are mixed and a curing reaction begins. The gelling/setting times for the curing reaction typically vary from several seconds to approximately 10 minutes. The anchor bolt is typically spun at a minimum ideal rotational speed of 100 revolutions/minute for between 3 and 10 seconds depending on the resin gel time (typically 20 to 60 revolutions). By gel time, it is meant the time that elapses between mixing of the reactive components and the hardening or stiffening of the resin in the mixture. The resin compartment may include a cross-linking agent (e.g., styrene) and inert filler material (e.g., limestone, silica, or sand). Production and filling of resin cartridges from a continuous film and sealing at the ends may be accomplished as described in U.S. Patent No. 4,239,105 to Gilbert, U.S. Patent Application Publication No. 2007/0017832 to Simmons et al., or U.S. Patent Application Publication No. 2008/0120947 to Oldsen et al., all incorporated herein by reference. Resin cartridges for mine roof support are typically ³A inch to 1 ¹A inch in diameter and 2 to 6 feet in length. The relationship between bore hole dimensions, bolt size, and the size and number of cartridges used in each bore hole is critical to good performance with such cartridges. [0004] Upon curing, resin cartridges, when used in connection with anchor bolts, often exhibit a uniaxial compressive strength of approximately 12,600 psi (86.8 N/mm²), a Young's Modulus of approximately 6.5 GPa, a tensile strength (beam test) of approximately 3,200 psi (22.1 N/mm²) and an unconfined shear strength of approximately 7,500 psi (52 N/mm²).

[0005] The cured resin may be resistant to acids and alkalis over a wide range of pH (for example, between pH 2 and pH 10). No significant weakening is observed even when constantly immersed in water. The cured resin is also long lasting and protects that portion of the anchor bolt to which the resin is bonded. The resin is also substantially unaffected by vibration (from blasting) after it is fully cured.

[0006] Resin grouts as described above exhibit thixotropic behavior, i.e., a decrease in viscosity of the material over time at constant shear. Thixotropy reduces viscosity during insertion of the bolt and enables relatively low installation force and torque. Resin grouts may be sufficiently thixotropic such that the resin does not run out of the holes before gelling or setting. The initial viscosity of the resin grout can, for example, be made relatively high, and different viscosity mixes are typically made for use in different applications. For example, lower viscosity mixes can be used if the annular space in the bore hole is limited or if the desired grout length is large.

[0007] Resin cartridges may be used to anchor a reinforcing member at the blind end of a bore hole as a point anchored bolt or may be used as a full column of a single-speed resin in a bore hole. Other applications use hybrid systems of a faster setting resin in the blind end of the bore hole and a slower setting resin in the remainder of the hole, thereby creating a pretension bolt.

[0008] Over-spinning and under-spinning of grouts including a polyester resin mix can be hazardous. In that regard, over-spinning causes the resin to become brittle and granular, while under-spinning prevents the thorough resin mixing required for complete setting. (0009J For maximum shelf life, polyester resin grout cartridges may have a shelf life of up to one year if properly stored. However, under adverse conditions, the shelf life is significantly reduced. Storage is recommended under cover on original pallets with adequate ventilation. If stored in trailers in hot weather, doors should be left ajar or a sun screen erected over the trailer. Conversely, while cold storage does not adversely affect the shelf life, cartridges should be warmed to a range of 50-60° F before using to assure gel times within the specified range.

[0010] A number of problems are associated with currently available resins for use in connection with anchor bolts and other reinforcing members, including, but not limited to: thorough mixing is required between the resin and the catalyst to achieve total setting or curing; over-mixing results in granulation and low strength; under-mixing results in inadequate or incomplete setting; prior to use, polyester resin cartridges are flammable; the resin bonds onto the reinforcing bar, but has only a mechanical key or frictional lock with the surrounding rock and the resins usually shrink slightly on setting; and the polyester resin is relatively expensive and requires expensive inert pure fillers as impurities, which can act to prematurely catalyze the polyester resin (such as iron ions).

SUMMARY OF THE INVENTION

(0011J The present invention includes a grout system for a reinforcing member comprising a first portion comprising a polymerizable component, said polyrøerizable component comprising essentially of acrylic resin; and a second portion comprising an activator for polymerizing said acrylic resin upon mixing of said first and second portions. Also included in the present invention is a mine roof control system comprising a reinforcing member; and a dual compartment resin cartridge comprising a first portion in one compartment and a second portion in another compartment, the first portion comprising a polymerizable component, the polymerizable component comprising essentially of acrylic resin; and the second portion comprising an activator for polymerizing the acrylic resin upon mixing of the first and second portions.

DETAILED DESCRIPTION OF THE INVENTION

[0012] The grout system of the present invention includes a first portion comprising a polymerizable component comprising curable or settable acrylic resin, which is substantially free of polyester resin, and a second portion comprising an activator for polymerization of the acrylic resin. By acrylic resin, it is meant thermoplastic or thermosetting plastic substances derived from acrylic acid, methacrylic acid, or other related compounds. By substantially free, it is meant that the acrylic resin component does not deliberately include precursors of polyester or epoxy-based polymers in amounts in excess of trace amounts. However, other polymer components may be included therein such as polyurethane. Acrylic resin component

[0013] Suitable acrylate or methacryϊate monomers for use in the acrylic resin component include mono-functional, di-functional, and tetra-functional monomers such as tetraethyleneglycol, isodecyl, hydroxyethyl, and hydroxypropyl esters of acrylic acid and methacrylic acid; butyl, isodecyl, methyl, tetrahydrofurfuryl, isobornyl, and 2-ethylhexyl esters of acrylic and methacrylic acid; diacrylates, dimethacrylates, triacrylates, trimethacrylates, tetraacrylates and tetramethacrylates of butyl eneglycol, tetraethyleneglycol, polyethylene glycol, bisphenol A, ethoxylated bisphenol A, pentaerythritol, and the like. It has been found that acrylic acid or acrylate sulfates, as well as vinyl functional acetate, chloride, or alcohol tend to improve adhesion between the resin and the reinforcing member. Mono-functional (meth)acrylic monomers may be present in an amount of 1-3 wt.% of the final grout composition. The total amount of di-functional, tri-functional, and tetra-functional (meth)acrylic monomers may be 1 -3 wt.% of the final grout composition. By final grout composition, it is meant the combination of the first and second portions upon mixing thereof.

[0014] More particularly, suitable acrylate and methacrylate monomers include 1,3- butylene glycol diacrylate; 1,4-butanediol diacrylate; 1 ,4-butanediol dimethacrylate; diethylene glycol diacrylate; diethylene glycol dimethacrylate; 1 ,6-hexanediol diacrylate; 1,6- hexanediol dimethacrylate; isodecyl methacrylate; neopentyl glycol diacrylate; neopentyl glycol dimethacrylate; monoethylene glycol acrylate methacrylate; polyethylene glycol (600) dimethacrylate; 2(2-ethoxyethoxy) ethyl acrylate; stearyl acrylate; polyethylene glycol (200) diacrylate; tetraethylene glycol diacrylate; Methylene glycol diacrylate; tetrahydrofurfuryl acrylate; pentaerythritol tetraacrylate; 1,3-butyiene glycol dimethacrylate; tripropylene glycol diacrylate; lauryl methacrylate; Ci₂-C]₄ alkyl methacrylate; stearyl methacrylate; lauryl acrylate; 2-phenoxyethyl acrylate; 2-phenoxyethyl methacrylate; polyethylene glycol (400) diacrylate; ethoxylated (2) bisphenol A dimethacrylate; ethoxylated (3) bisphenol A diacrylate; trimethylolpropane trimethacrylate; trimethylolpropane triacrylate; di- trimethylolpropane tetraacrylate; tris (2-hydroxy ethyl) isocyanurate triacrylate; isodecyl acrylate; dipentaerythritol pentaacrylate; ethoxylated (20) trimethylolpropane triacrylate; isobornyl methacrylate; isooctyl acrylate; pentaerythritol triacrylate; ethoxylated (3) trimethylolpropane triacrylate; octyldecyl acrylate; nonyl phenolmethacrylate; tridecyl acrylate; propoxylated (3) tiimethylolpropane triacrylate; tridecyl methacrylate; ethoxylated (4) pentaerythritol tetraacrylate; caprolactone acrylate; ethoxylated (6) trimethylolpropane triacrylate; ethoxylated (9) trimethylolpropane triacrylate; ethoxylated (4) nonyl phenol acrylate; isobomyl acrylate; dipropylene glycol diacrylate; cyclic trimethylolpropane formal acrylate; acrylic esters; ethoxylated (4) bisphenol A dimethacrylate; ethoxylated (6) bisphenol A dimethacrylate; methoxy polyethylene glycol (350) monomethacrylate; ethoxylated (4) bisphenol A diacrylate; ethoxylated (10) bisphenol A diacrylate; polyethylene glycol (400) dimethacrylate; polyethylene glycol (600) diacrylate; alkoxylated nonylphenol acrylate; polyethylene glycol (1000) dimethacrylate; tricyclodecane dimethanol diacrylate; propoxylated neopentyl glycol diacrylate; trifunctional methacrylate esters; trifunctional acrylate esters; metallic diacrylate; propoxylated (3) glyceryl triacrylate; ethoxylated (15) trimethylolpropane triacrylate; ethoxylated (8) bisphenol A dimethacrylate; ethoxylated (30) bisphenol A dimethacrylate; ethoxylated (30) bisphenol A diacrylate; pentaacrylate ester; alkoxylated neopentyl glycol diacrylate; alkoxylated aliphatic diacrylate; tetrahydrofurfuryl methacrylate; triethylene glycol dimethacrylate; ethylene glycol dimethacrylate; tetraethylene glycol dimethacrylate; polyethylene glycol dimethacrylate; 1,12-dodecanediol dimethacrylate; cyclohexane dimethanol dimethacrylate; cyclohexane dimethanol diacrylate; 3,3,5-trimethylcyclohexyl methacrylate; propoxylated (6) trimethylolpropane triacrylate; dicyclopentadienyl methacrylate; diethylene glycol methyl ether methacrylate; methoxy polyethylene glycol (350) monoacrylate; methoxy polyethylene glycol (550) monomethacrylate; methoxy polyethylene glycol (550) monomethacrylate; methoxy polyethylene glycol (550) monoacrylate; alkoxylated hexanediol diacrylate; alkoxylated cyclohexane dimethanol diacrylate; alkoxylated tetrahydrofurruryl acrylate; ethoxylated (4) nonyl phenol methacrylate; ethoxylated nonyl phenol acrylate; triethylene glycol ethyl ether methacrylate; alkoxylated dϊacrylates; highly propoxylated (5.5) glyceryl triacrylate; alkoxylated neopentyl glycol diacrylate; alkoxylated lauryl acrylate and alkoxylated phenol acrylate.

[0015] Other suitable acrylate or methacrylate monomers include metallic monomers such as magnesium acrylate or methacrylate; alumina acrylate or methacrylate; zinc acrylate or methacrylate; potassium acrylate or methacrylate; sodium acrylate or methacrylate; ferrate acrylate or methacrylate; and calcium acrylate or methacrylate. In one embodiment of the present invention, the metallic (meth)acrylate monomers are 7-30 wt.% of the final grout composition. Activator component

[0016] Suitable activators for polymerizing the monomers of the acrylic resin component are oxidizing agents such as ammonium perchlorate, ferric chloride, magnesium chloride, zinc chloride, salpetre, nitrites, potassium nitrate (KNO₃), hypochlorite (and other hypohalite compounds such as bleach), iodine and other halogens, chlorite, chlorate, perchlorate, and other analogous halogen compounds, permanganate salts, ammonium cerium (IV) nitrate and related cerium (IV) compounds, hexavalent chromium compounds such as chromic and dichromic acids and chromium trioxide, pyridinium chlorochromate (PCC), and chromate/dichromate compounds, peroxide compounds, Tollen's Reagent, sulfoxides, persulfuric acid, ozone, osmium tetroxide (OsO₄), nitric acid, and nitrous oxide. The activator is present in the grout system in an amount of a trace up to 10 wt.% of the final grout composition. Additives

[0017] Depending on the specific acrylic resin used, various additives may be included in the grout system of the present invention including inert fillers, viscosifiers, stabilizers, inhibitors, and accelerators.

[0018] Fillers may be various inert organic or inorganic compounds. Suitable fillers include, but are not limited to, fly ash, calcium carbonate, lime, silica particles, or silica flour (a silica sand ground to a fine particle size), talc, magnesium carbonate, mica, magnesium oxide, and kaolin (in fiber or aggregate form) or mixtures thereof. Fly ash is a residue generated in the combustion of coal. Fly ash is generally captured from the chimneys of power generation facilities, whereas bottom ash is removed from the bottom of the furnace. Fly ash typically includes, for example, silicon dioxide (SiO₂), aluminum oxide (AI₂O₃), iron oxide (Fe₂O₃), and calcium oxide or lime (CaO) in varying ranges depending upon the type of coal that is burned. Fillers are relatively inexpensive compounds as compared to polyester resin and may be included in the grout system of the present invention in an amount of 50-93 wt.%. The cost of producing the grout system of the present invention can be minimized by the use of fillers in these amounts. Fly ash has a lower density than most other fillers (especially as compared to limestone fillers traditionally used with polyester resins) and since resin cartridges are sold by volume, less filling is needed per unit volume thereby reducing the cost of resin cartridges.

[0019] Inhibitors (also terminal stabilizers) may be included in the acrylic resin component to control gel time and minimize premature polymerization. Inhibitors may also be used to extend shelf life of the grout system. Suitable materials for these purposes include hydroquinone, vitamin C, vitamin E, acetic acid, citric acid, phenolHc compounds, copper compounds, cyanides, benzoquinone, napthoquinone, p-methoxyphenol, and 2,6-di-t-butyl-p- cresol. Inhibitors may be included in amounts of about 50-400 ppm up to 1-2 wt.% of the total grout system.

[0020] Accelerators may be included in the acrylic resin component in an amount of 0.5-40 wt.% of the total grout system to shorten the gel time. Examples of suitable accelerators include ferrous ions, lithium aluminum hydride (LiAlH₄)_J nascent hydrogen, sodium amalgams, sodium borohydride, stannous ions, sulfite compounds, hydrazine, zinc-mercury amalgams, diisobutylaluminum hydride, Lindlar catalyst, oxalic acid, formic acid, ethanolamines and other amines, nitrates, magnesium oxide, hydroxides, and magnesium octoate.

[0021] Expansion agents may be included in the grout system of the present invention, such as in the acrylic resin component, IE one embodiment of the present invention, use of an expansion agent may increase the strength of the bond (referred to as the mechanical key) between the reinforcing member and the surrounding rock. This may be particularly desirable in weak rock formations.

[0022] Other additives may be used to compensate for any shortage that occurs upon curing of the acrylic resin. For example, mica powder may be included in the grout system, which provides some compensation for loss of volume without sacrificing mechanical properties.

[0023] One benefit of increasing the strength of the mechanical key occurs when partially grouted anchors (for example, bolts or cables) are used. In these applications, improving the mechanical key can improve the factor of safety. Improving the strength of the mechanical key can also enable reduction of the effective bond length, thereby creating a cost saving without a decrease in bolt performance. The strength of the mechanical key can, for example, be improved by making the grout expand. Such expansion can be achieved by, for example, gaseous expansion prior to complete setting. Gaseous expansion may be used to achieve grout expansion and may be balanced against any reduction in the mechanical properties of the set grout (i.e., reduced compressive strength, tensile stress, shear stress, etc.). However, by controlling the gaseous expansion, sufficient mechanical strength can be maintained. [0024] In that regard, currently available resin grouts exhibit higher tensile strength, shear strength, and other mechanical properties than necessary. By improving the strength of the mechanical key, even at the expense of the other mechanical properties, the set anchor grout system can be balanced such that the overall performance (for example, pull-out load capacity per unit length) of the grout system is improved. [0025] In one embodiment of the present invention, an expansion agent is included in the grout in an amount whereby the final set expansion is limited to 10% or less (of the un- expanded equivalent volume). For example, the expansion may be limited to 4% or less. [0026] One suitable type of expansion agent of the present invention reacts upon contact with one or more other components or otherwise under certain conditions, conditions can be maintained such that reaction does not occur until initiation of the curing or setting reaction. In the case of use of a grout system including acrylic resin, an expansion agent such as sodium bicarbonate (NaHCOs) can be included in the portion including no water (i.e., in the resin portion). Sodium bicarbonate decomposes via reaction with an acid or via thermal decomposition to produce carbon dioxide. The carbon dioxide is trapped within the setting grout and results in expansion of the grout as compared to an equivalent grout not including sodium bicarbonate. Upon mixing of the components as described above, the setting reaction and the reaction of sodium bicarbonate are initiated. In several embodiments, sodium bicarbonate can, for example, be present up to approximately 2 wt.% or up to approximately 1 wt.%.

[0027] The grout system of the present invention contains substantially no polyester resin and exhibits a number of advantages as compared to currently available grouts that include polyester resins. For example, unlike polyester resins, if the acrylic resin and catalyst of the present invention are not properly mixed, the mix will tend to set over time to provide some mechanical properties. Moreover, the grouts of the present invention exhibit less sensitivity to some impurities in fillers (for example, fly ash). Acrylic resins used in the grout system of the present invention are typically less expensive than polyester resins used in currently available grouts. Moreover, the acrylic resins of the grouts of the present invention can be diluted (having filler) more than polyester resins used in currently available grouts, thereby further reducing the cost. Further, the acrylic resins used in the grout system of the present invention are safer and less hazardous materials (e.g., less flammable) than the polyester resins used in currently available grouts. Still further, the grouts of the present invention exhibit improved mechanical properties/anchoring performance (for example, higher shear strength).

[0028] The resin grout system of the present invention exhibits similar or improved shelf life to that of currently available polyester resin grouts. Moreover, the cured resin of the present invention is resistant to acids and alkalis over a wide range of pH (for example, between pH 2 and pH 10). No significant weakening is observed even when constantly immersed in water. The cured resin grouts are also long lasting and protect that portion of the bolt or other reinforcement member to which the resin is bonded. The cured resin of the present invention is also substantially unaffected by vibration (from blasting) after it is fully cured. Another significant advantage of the acrylic resin grout system is that if only partially mixed, the material will still tend to set relatively hard throughout, unlike catalyzed polyester resin cartridges.

(0029] In another embodiment of the present invention, the grout system includes a foaming agent that upon mixture of the first portion containing the foaming agent with the second portion, the volume of the grout system increases by at least 300%, such as by 400% or more, such as 1000%. The foaming agent described herein is suited for use in the grout system of the present invention and may also be used in cementitious based grouts, polyester based grouts, or combinations thereof. When increased corrosion protection is needed for the reinforcing member, fully grouting the annulus of a bore hole surrounding the reinforcing member may be costly in terms of the volume of the grout needed. Alternatively, if the grout system of the present invention is expanded using a foaming agent, less resin grout is required. Typically, a cable bolt approximately 10 to 16 feet long is grouted for only about 4 to 6 feet of its length. However, expansion of over 300% of a grout system can significantly increase the length of the reinforcing member that is surrounded by the foamed grout. Foaming of the grout system typically requires less filler content and can alter the mechanical properties associated with unfoamed grout systems. Accordingly, the present invention also contemplates the use of an unfoamed grout system in combination with a foamed grout system. For example, the blind end of a bore hole may be grouted using an unfoamed grout system as a point anchor whereas the remainder of the reinforcing member may be grouted with a foamed grout system, thereby acting as a corrosive protecting agent for the bulk of the length of the reinforcing member,

[0030J Suitable foaming agents include sodium bicarbonate, which decomposes in reaction to an acid or by thermal decomposition to produce carbon dioxide. The amount of foaming agent that is included is controlled to provide the desired amount of the expansion of the grout system such as 300% or more, such as 1000%, via a closed cell foam. Fillers may also be added to reduce cost and increase the thixotrophy of the system.

(0031] Alternatively, a foaming system may be added to the grout system of the present invention such as a polyurethane foam based on mono-functional isocyanate compounds. Examples of mono-functional isocyanate which may be used to produce a polyurethane foam include toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), or aliphatic multiisocynates, such as hexamethylene diisocyanate (HDI), l-isocyanato-3~ isocyanatomethyW^S-trimemyl-cyclohexane (isophorone diisocyanate, or IPDI)₅ and 4,4'- diisocyanato dicyclohexylmethane (H₁2MDI).

[0032] In addition to the cartridge embodiments, discussed above, the grout systems of the present invention can also be pumped into drill holes. For example, the two components of the grout system can be mixed upon delivery using a twin metered pump and an in-line mixer at the discharge nozzle of the pump.

EXAMPLES

Example 1 [0033] A resin grout system was prepared using the following components:

[0034] The acrylates and fly ash were mixed together in a high shear mixer. The oxidizer and water were added to the mixture, resulting in a composition having a viscosity of 160,000 cps.

[0035] The resin mixture (66.6 g) was mixed with 33.4 g of a fly ash/sulphite mixture

(160,000 cps), yielding the following properties:

Example 2 [0036] Resin grout systems having the following components were prepared.

[0037] Mechanical properties of the grout are summarized in Table 1. The properties are an average of three tests.

Table 1

Example 3

[0038] The viscosity of resin compositions of polyester with limestone versus the grout composition of the present invention (acrylic resin and fly ash) were compared as shown in Table 2. Depending on the specific application for the resin cartridges, the conventional polyester resin cartridges contain between 14% and 17% polyester resin.

Table 2

[0039] This data shows that a greater proportion of fly ash can be used than limestone to obtain a resin composition with a desired viscosity. As a result, the grout system of the present invention is less costly than prior polyester/limestone grout systems, since fly ash may constitute a larger proportion, thereby minimizing the amount of acrylic resin used therewith. In addition, the acrylic resin grout system of the present invention presents lower risks to users than polyester resin systems in terms of health and safety issues and flammability. [0040] The foregoing description sets forth the preferred embodiments of the invention at the present time. Various modifications, additions, and alternative designs will, of course, become apparent to those skilled in the art in light of the foregoing teachings without departing from the scope of the invention. The scope of the invention is indicated by the following claims rather than by the foregoing description. All changes and variations that fall within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

THE ΪNVENTION CLAIMED IS

1. A grout system for a reinforcing member comprising: a first portion comprising a polymerizable component, said polymerizable component consisting essentially of acrylic resin; and a second portion comprising an activator for polymerizing said acrylic resin upon mixing of said first and second portions.

2. The grout system of claim 1, wherein said polymerizable component comprises about 5-40 wt.% of the grout system.

3. The grout system of claim 1, wherein said acrylic resin comprises a metal acrylate, a mono-functional methacrylate, and/or a multi-functional methacrylate.

4. The grout system of claim 3, wherein said acrylic resin comprises a trivalent metal methacrylate, ethylene glycol methacrylate, and/or polyethylene glycol dimethacrylate.

5. The grout system of claim 1, wherein said activator comprises an oxidizing agent

6. The grout system of claim 1, wherein said first portion further comprises another polymeric material.

7. The grout system of claim 1 , further comprising an expansion agent.

8. The grout system of claim 7, wherein the grout system expands by up to about 10% upon reaction with said expansion agent.

9. The grout system of claim 7, wherein the grout system expands by at least 100% upon reaction with said expansion agent.

10. 10. A mine roof control system comprising: a reinforcing member; and a dual compartment resin cartridge comprising a first portion in one compartment and a second portion in another compartment, said first portion comprising a polymerizable component, said polymerizable component consisting essentially of acrylic resin; and said second portion comprising an activator for polymerizing said acrylic resin upon mixing of said first and second portions.

11. The mine roof system of claim 10₅ wherein said reinforcing member comprises a rock bolt or a cable bolt.

12. The mine roof system of claim 10, wherein said polymerizable component comprises about 5-40 wt.% of the grout system.

13. The mine roof system of claim 10, wherein said acrylic resin comprises a metal acrylate, a mono-functional methacrylate, and/or a multi-functional methacrylate.

14. The mine roof system of claim 10, wherein said acrylic resin comprises a trivalent metal methacrylate, ethylene glycol methacrylate, and/or polyethylene glycol dimethacrylate.

15. The mine roof system of claim 10, wherein said activator comprises an oxidizing agent.

16. In a mine roof resin cartridge comprising a first compartment containing a resin component and a second compartment containing a reactant for polymerizing the resin component, the improvement comprising said resin component consisting essentially of an acrylic resin.

17. The resin cartridge of claim 16, wherein said acrylic resin comprises a metal aery late, a mono-functional methacrylate, and/or a multi-functional methacrylate.

18. The resin cartridge of claim 16, wherein said polymerizing reactant comprises an oxidizing agent.

19. The mine roof system of claim 16, wherein said first compartment further contains another polymeric material.

20. The mine roof system of claim 16, wherein said first compartment further contains an expansion agent.