Goaf Inertisation and Sealing Utilising Methane from In-Seam Gas Drainage System

In the past the process for sealing longwall goafs at Mandalong has been to simply seal access points to the goaf and monitor the goaf as it self inertised. Due to changes in legislative requirements an improved method was required. A number of different methods utilising N2 or CO2 have been utilised at other mine sites. However, at Mandalong it was decided to use methane from the in-seam gas drainage system to purge and inertise the goaf. According to our knowledge this is the first time this method of utilising methane for goaf inertisation and sealing has been implemented. The aim of the sealing process is to seal the goaf in a safe manner without disruption to other parts of the mine. This is achieved by controlling the inertisation process through the introduction of methane from the gas drainage system with the intent of purging the critical zone of the unsealed goaf of any oxygen. Methane from the mine’s gas drainage system and existing pipe arrangement is re-directed to the seals behind the longwall take-off face and injected into the goaf fringe under seam pressure. The goaf atmosphere is monitored via a tube bundle system and is allowed to enter and exit the explosive range under controlled conditions. When the tube bundle monitoring shows the goaf atmosphere is inert, final sealing of the goaf is carried out. The principal hazard associated with the sealing of a goaf area in a gassy mine is the ignition of an explosive atmosphere resulting in an explosion. To reduce this risk to as low as reasonably possible (ACARP) numerous controls are implemented. Mandalong has successfully utilised this method four times since February 2008. Longwall 5 (LW5), Longwall 6 (LW6), Longwall 7 (LW7), Longwall 8 (LW8) and Longwall 9 (LW9) were sealed in this manner, and it is intended future longwall goafs be sealed utilising the same methodology. The results of these will be presented and discussed

Crop Insurance, Disaster Payments and Land Use Change: The Effect of Sodsaver on Incentives for Grassland Conversion

Subsidized crop insurance may encourage conversion of native grassland to cropland. The Sodsaver provision of the 2008 farm bill could deny crop insurance on converted land in the Prairie Pothole states for 5 years. Supplemental Revenue Assistance payments, which are linked to crop insurance purchases, could also be withheld. Using representative farms, we estimate that Sodsaver would reduce expected crop revenue by up to 8% and expected net return by up to 20%, while increasing the standard deviation of revenue by as much as 6% of market revenue. Analysis based on elasticities from the literature suggests that Sodsaver would reduce grassland conversion by 9% or less.bootstrap, crop insurance, grassland, joint densities, Sodsaver, Supplemental Revenue Assistance, Agricultural and Food Policy, Production Economics, Risk and Uncertainty, Q2,

EFFECTS OF AGRI-ENVIRONMENTAL PAYMENT POLICIES ON AGRICULTURAL TRADE

In many OECD countries, including the U.S., interest in developing agri-environmental payment programs is currently strong. In the future, the inclusion of an agri-environmental payment program into the WTO's "green box" could be more easily challenged by WTO member countries on the basis that it has more than "minimal" trade-distorting impacts on production. The goal of this paper is to conduct an ex ante analysis of the trade impacts of stylized examples of agri-environmental payment programs that have been proposed for implementation in the near future. To simulate the production and trade impacts of these programs, we use a partial equilibrium model of the U.S. agricultural sector in a sensitivity analysis across a range of design options for agri-environmental payments. For the three agri-environmental payment scenarios evaluated, the maximum change in exports ranges from a 7 percent decrease (wheat) to a 1 percent increase (soybeans). We do not expect the programs that decrease U.S. production, which would tend to have an upward pressure on world commodity prices, to be challenged before the WTO.Agricultural and Food Policy,

Crop Insurance, Disaster Payments, and Incentives for Land Use Change in Agriculture: A Preliminary Assessment

Crop Insurance, Disaster Payments, Supplemental Revenue Assistance, corn, wheat, Agricultural and Food Policy, Research Methods/ Statistical Methods, Risk and Uncertainty,

NEW CONSERVATION INITIATIVES IN THE 2002 FARM BILL

The role of agri-environmental programs has taken on increased importance in the current Farm Bill debate with an eighty percent increase in Title II funding. However, little empirical evidence exists on the tradeoffs between economic costs and environmental benefits of new agri-environmental programs to assist policymakers in their designs. This paper illustrates some of the budgetary and environmental issues inherent in these initiatives. Several policy options are explored using an environmental simulation model and an economic spatial-equilibrium model for U.S. agriculture. Results indicate abatement levels of nitrogen and pesticides are higher under performance-based policies and those for wind erosion and soil productivity are higher under practice-based policies. Abatement of phosphorus discharge, soil erosion and carbon sequestration remains relatively constant regardless of policy type. A national performance-based conservation policy funded at the $1 billion level has the potential to improve the environmental performance of U.S. farmers by as much as ten percent.Agricultural and Food Policy, Land Economics/Use,

ENVIRONMENTAL RISK AND AGRI-ENVIRONMENTAL POLICY DESIGN

Agricultural nonpoint pollution is inherently stochastic (e.g., due to weather). In theory, this randomness has implications for the choice and design of policy instruments. However, very few empirical studies have modeled natural variability. This paper investigates the importance of stochastic processes for the choice and design of alternative nonpoint instruments. The findings suggest that not explicitly considering the stochastic processes in the analysis can produce significantly biased results.Agricultural and Food Policy, Environmental Economics and Policy,

Flexible Conservation Measures on Working Land: What Challenges Lie Ahead?

From 1985 to 2002, most Federal conservation dollars going to farm operators have been to retire land from crop production. Yet most U.S. farmland (850 million acres) remains in active production. The Farm Security and Rural Investment (FSRI) Act of 2002 sharply increased conservation funding and earmarked most of the increase for working-land payment programs (WLPPs). The design and implementation of WLPPs will largely determine the extent to which environmental goals are achieved and whether they are cost effective. We simulate potential environmental gains as well as adjustments in agricultural production, price, and income associated with various WLPP features to illustrate tradeoffs arising from WLPP design and implementation. Competitive bidding with the use of environmental indices to rank producers for enrollment is most cost effective. Payments based on past conservation will help support farm incomes, but limit the amount of additional environmental benefit that can be generated under a fixed budget.Land Economics/Use,

Grassland to Cropland Conversion in the Northern Plains: The Role of Markets and Policy

Crop Production/Industries, Land Economics/Use,

Analysis of Ethane Emission Trends from Active Goaf Seals at Mandalong Mine

Monitoring of active goaf seals at Mandalong Mine shows anomalous levels of ethane concentrations. Currently ethane concentrations exceeding 250 ppm have been experienced from 30 to 32 C/T seals of MG8 with the remainder of the panel averaging 50 - 100 ppm. Active goaf seals for MG7 and MG9 average 50 - 100 ppm and 80 - 100 ppm, respectively. For most mines these concentrations of ethane would be assumed to indicate a spontaneous combustion event; however no carbon monoxide is being recorded and a sympathetic relationship with methane indicates that the measured ethane is due to gas desorption. This paper presents the results from the mine showing trends in ethane emissions from the active goaf seals to date, and shows how this historical data can be used to predict expected ethane concentrations in the active goaf of MG10

ENVIRONMENTAL COMPLIANCE IN U.S. AGRICULTURAL POLICY: PAST PERFORMANCE AND FUTURE POTENTIAL

Since 1985, U.S. agricultural producers have been required to practice soil conservation on highly erodible cropland and conserve wetlands as a condition of farm program eligibility. This report discusses the general characteristics of compliance incentives, evaluates their effectiveness in reducing erosion in the program's current form, and explores the potential for expanding the compliance approach to address nutrient runoff from crop production. While soil erosion has, in fact, been reduced on land subject to Conservation Compliance, erosion is also down on land not subject to Conservation Compliance, indicating the influence of other factors. Analysis to isolate the influence of Conservation Compliance incentives from other factors suggests that about 25 percent of the decline in soil erosion between 1982 and 1997 can be attributed to Conservation Compliance. This report also finds that compliance incentives have likely deterred conversion of noncropped highly erodible land and wetland to cropland, and that a compliance approach could be used effectively to address nutrient runoff from crop production.conservation compliance, Sodbuster, Swampbuster, conservation policy, agri-environmental policy, nutrient management, buffer practices, Agricultural and Food Policy,