Gas-generating compositions, fracturing system and method of fracturing material

Abstract

Compositions and systems for use in breaking or fracturing hard material are described. In particular, gas-generating compositions exhibiting at least a dual burn rate, including compositions comprising lactose, potassium perchlorate and ferrosilicon are described.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 649,992, filed Feb. 4, 2005, which is incorporated by reference in its entirety.STATEMENT OF RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH [0002] Not applicable. TECHNICAL FIELD [0003] This invention relates to material breaking or fracturing methods and compositions and systems useful therein. More specifically, it relates to gas-generating compositions, fracturing systems, and methods of using and making the foregoing. BACKGROUND OF THE INVENTION [0004] Excavation of hard materials, such as rock and concrete, is a primary activity in underground mining, surface mining, open pits and quarries, earth moving and allied construction works, and in civil demolition projects. Explosive blasting has historically been used to break hard materials during excavation, but this technique is not suitable for all applications due to handling and safety concerns...

AI Technical Summary

Problems solved by technology

Explosive blasting has historically been used to break hard materials during excavation, but this technique is not suitable for all applications due to handling and safety concerns that accompany the use of high explosive materials.

For instance, explosive blasting is known to produce noise, vibration and flyrock, and explosive materials are subject to strict handling and transportation restrictions.

However, these techniques require expensive and highly specialized tools.

Moreover, repetitive breaking can result in wear and dulling of the machinery over time which can require sharpening or replacing expensive machine parts.

This is a relatively safe method, but also relies on sophisticated and expensive equipment that has a limited lifetime due to the degradation accompanying repeated firings.

In some applications, high explosives cannot be used due to regulatory restrictions and mechanical breaking means are impractical due to the material's location and / or high compressive strength.

While this method offers a potential alternative to conventional means, it is not without drawbacks.

The propellant formulas disclosed are known to be hygroscopic and have a high tendency to misfire, which is both costly and dangerous.

In addition, the fracturing efficiencies disclosed, commonly expressed as the powder factor by those skilled in the art of the propellants, are relatively low, leading to higher drilling, boring, and cartridge costs.

This combined method provides improved efficiency over either method when used alone, but does not overcome the problems of regulatory restrictions and the high cost of transport and safety when using a high explosive material.

Deflagrating compositions used in small charge breaking applications are safer than high explosives, but can provide insufficient results due to the time required to produce enough gas to fracture the material.

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